Refactored the DragAndDropTarget callback methods, to replace the parameters with a structure. This also affects the TreeViewItem drag-and-drop callback methods.

extras/Introjucer/Source/Project/jucer_ProjectTreeViewBase.cpp

@@ -336,21 +336,21 @@ void ProjectTreeViewBase::getAllSelectedNodesInTree (Component* componentInTree,
     }
 }
 
-bool ProjectTreeViewBase::isInterestedInDragSource (const String& sourceDescription, Component* sourceComponent)
+bool ProjectTreeViewBase::isInterestedInDragSource (const DragAndDropTarget::SourceDetails& dragSourceDetails)
 {
-    if (sourceDescription != projectItemDragType)
+    if (dragSourceDetails.description != projectItemDragType)
         return false;
 
     OwnedArray <Project::Item> selectedNodes;
-    getAllSelectedNodesInTree (sourceComponent, selectedNodes);
+    getAllSelectedNodesInTree (dragSourceDetails.sourceComponent, selectedNodes);
 
     return selectedNodes.size() > 0 && acceptsDragItems (selectedNodes);
 }
 
-void ProjectTreeViewBase::itemDropped (const String& sourceDescription, Component* sourceComponent, int insertIndex)
+void ProjectTreeViewBase::itemDropped (const DragAndDropTarget::SourceDetails& dragSourceDetails, int insertIndex)
 {
     OwnedArray <Project::Item> selectedNodes;
-    getAllSelectedNodesInTree (sourceComponent, selectedNodes);
+    getAllSelectedNodesInTree (dragSourceDetails.sourceComponent, selectedNodes);
 
     if (selectedNodes.size() > 0)
     {

extras/Introjucer/Source/Project/jucer_ProjectTreeViewBase.h

@@ -92,8 +92,8 @@ public:
     // Drag-and-drop stuff..
     bool isInterestedInFileDrag (const StringArray& files);
     void filesDropped (const StringArray& files, int insertIndex);
-    bool isInterestedInDragSource (const String& sourceDescription, Component* sourceComponent);
-    void itemDropped (const String& sourceDescription, Component* sourceComponent, int insertIndex);
+    bool isInterestedInDragSource (const DragAndDropTarget::SourceDetails& dragSourceDetails);
+    void itemDropped (const DragAndDropTarget::SourceDetails& dragSourceDetails, int insertIndex);
 
     static void getAllSelectedNodesInTree (Component* componentInTree, OwnedArray <Project::Item>& selectedNodes);
 

extras/JuceDemo/Source/demos/DragAndDropDemo.cpp

@@ -133,7 +133,7 @@ public:
     // These methods implement the DragAndDropTarget interface, and allow our component
     // to accept drag-and-drop of objects from other Juce components..
 
-    bool isInterestedInDragSource (const String& /*sourceDescription*/, Component* /*sourceComponent*/)
+    bool isInterestedInDragSource (const SourceDetails& /*dragSourceDetails*/)
     {
         // normally you'd check the sourceDescription value to see if it's the
         // sort of object that you're interested in before returning true, but for
@@ -141,25 +141,25 @@ public:
         return true;
     }
 
-    void itemDragEnter (const String& /*sourceDescription*/, Component* /*sourceComponent*/, int /*x*/, int /*y*/)
+    void itemDragEnter (const SourceDetails& /*dragSourceDetails*/)
     {
         somethingIsBeingDraggedOver = true;
         repaint();
     }
 
-    void itemDragMove (const String& /*sourceDescription*/, Component* /*sourceComponent*/, int /*x*/, int /*y*/)
+    void itemDragMove (const SourceDetails& /*dragSourceDetails*/)
     {
     }
 
-    void itemDragExit (const String& /*sourceDescription*/, Component* /*sourceComponent*/)
+    void itemDragExit (const SourceDetails& /*dragSourceDetails*/)
     {
         somethingIsBeingDraggedOver = false;
         repaint();
     }
 
-    void itemDropped (const String& sourceDescription, Component* /*sourceComponent*/, int /*x*/, int /*y*/)
+    void itemDropped (const SourceDetails& dragSourceDetails)
     {
-        message = "last rows dropped: " + sourceDescription;
+        message = "last rows dropped: " + dragSourceDetails.description;
 
         somethingIsBeingDraggedOver = false;
         repaint();

juce_amalgamated.cpp

@@ -4576,7 +4576,7 @@ const var var::invoke (const var& targetObject, const var* arguments, int numArg
 
 const var var::call (const Identifier& method) const
 {
-	return invoke (method, 0, 0);
+	return invoke (method, nullptr, 0);
 }
 
 const var var::call (const Identifier& method, const var& arg1) const
@@ -18682,7 +18682,7 @@ ApplicationCommandTarget* ApplicationCommandManager::findTargetForComponent (Com
 
 	if (target == nullptr && c != nullptr)
 		// (unable to use the syntax findParentComponentOfClass <ApplicationCommandTarget> () because of a VC6 compiler bug)
-		target = c->findParentComponentOfClass ((ApplicationCommandTarget*) 0);
+		target = c->findParentComponentOfClass ((ApplicationCommandTarget*) nullptr);
 
 	return target;
 }
@@ -18811,7 +18811,7 @@ ApplicationCommandTarget* ApplicationCommandTarget::findFirstTargetParentCompone
 
 	if (c != nullptr)
 		// (unable to use the syntax findParentComponentOfClass <ApplicationCommandTarget> () because of a VC6 compiler bug)
-		return c->findParentComponentOfClass ((ApplicationCommandTarget*) 0);
+		return c->findParentComponentOfClass ((ApplicationCommandTarget*) nullptr);
 
 	return nullptr;
 }
@@ -55836,15 +55836,14 @@ void Toolbar::buttonClicked (Button*)
 	}
 }
 
-bool Toolbar::isInterestedInDragSource (const String& sourceDescription,
-										Component* /*sourceComponent*/)
+bool Toolbar::isInterestedInDragSource (const SourceDetails& dragSourceDetails)
 {
-	return sourceDescription == toolbarDragDescriptor && isEditingActive;
+	return dragSourceDetails.description == toolbarDragDescriptor && isEditingActive;
 }
 
-void Toolbar::itemDragMove (const String&, Component* sourceComponent, int x, int y)
+void Toolbar::itemDragMove (const SourceDetails& dragSourceDetails)
 {
-	ToolbarItemComponent* const tc = dynamic_cast <ToolbarItemComponent*> (sourceComponent);
+	ToolbarItemComponent* const tc = dynamic_cast <ToolbarItemComponent*> (dragSourceDetails.sourceComponent.get());
 
 	if (tc != nullptr)
 	{
@@ -55852,7 +55851,7 @@ void Toolbar::itemDragMove (const String&, Component* sourceComponent, int x, in
 		{
 			if (tc->getEditingMode() == ToolbarItemComponent::editableOnPalette)
 			{
-				ToolbarItemPalette* const palette = tc->findParentComponentOfClass ((ToolbarItemPalette*) 0);
+				ToolbarItemPalette* const palette = tc->findParentComponentOfClass ((ToolbarItemPalette*) nullptr);
 
 				if (palette != nullptr)
 					palette->replaceComponent (tc);
@@ -55872,7 +55871,8 @@ void Toolbar::itemDragMove (const String&, Component* sourceComponent, int x, in
 			const int currentIndex = items.indexOf (tc);
 			int newIndex = currentIndex;
 
-			const int dragObjectLeft = vertical ? (y - tc->dragOffsetY) : (x - tc->dragOffsetX);
+			const int dragObjectLeft = vertical ? (dragSourceDetails.localPosition.getY() - tc->dragOffsetY)
+												: (dragSourceDetails.localPosition.getX() - tc->dragOffsetX);
 			const int dragObjectRight = dragObjectLeft + (vertical ? tc->getHeight() : tc->getWidth());
 
 			const Rectangle<int> current (Desktop::getInstance().getAnimator()
@@ -55914,9 +55914,9 @@ void Toolbar::itemDragMove (const String&, Component* sourceComponent, int x, in
 	}
 }
 
-void Toolbar::itemDragExit (const String&, Component* sourceComponent)
+void Toolbar::itemDragExit (const SourceDetails& dragSourceDetails)
 {
-	ToolbarItemComponent* const tc = dynamic_cast <ToolbarItemComponent*> (sourceComponent);
+	ToolbarItemComponent* const tc = dynamic_cast <ToolbarItemComponent*> (dragSourceDetails.sourceComponent.get());
 
 	if (tc != nullptr && isParentOf (tc))
 	{
@@ -55926,9 +55926,9 @@ void Toolbar::itemDragExit (const String&, Component* sourceComponent)
 	}
 }
 
-void Toolbar::itemDropped (const String&, Component* sourceComponent, int, int)
+void Toolbar::itemDropped (const SourceDetails& dragSourceDetails)
 {
-	ToolbarItemComponent* const tc = dynamic_cast <ToolbarItemComponent*> (sourceComponent);
+	ToolbarItemComponent* const tc = dynamic_cast <ToolbarItemComponent*> (dragSourceDetails.sourceComponent.get());
 
 	if (tc != nullptr)
 		tc->setState (Button::buttonNormal);
@@ -56076,7 +56076,7 @@ private:
 		{
 			Colour background;
 
-			DialogWindow* const dw = findParentComponentOfClass ((DialogWindow*) 0);
+			DialogWindow* const dw = findParentComponentOfClass ((DialogWindow*) nullptr);
 
 			if (dw != nullptr)
 				background = dw->getBackgroundColour();
@@ -57333,9 +57333,10 @@ void TreeView::hideDragHighlight() noexcept
 }
 
 TreeViewItem* TreeView::getInsertPosition (int& x, int& y, int& insertIndex,
-										   const StringArray& files, const String& sourceDescription,
-										   Component* sourceComponent) const noexcept
+										   const StringArray& files, const SourceDetails& dragSourceDetails) const noexcept
 {
+	x = dragSourceDetails.localPosition.getX();
+	y = dragSourceDetails.localPosition.getY();
 	insertIndex = 0;
 	TreeViewItem* item = getItemAt (y);
 
@@ -57350,7 +57351,7 @@ TreeViewItem* TreeView::getInsertPosition (int& x, int& y, int& insertIndex,
 	if (item->getNumSubItems() == 0 || ! item->isOpen())
 	{
 		if (files.size() > 0 ? item->isInterestedInFileDrag (files)
-							 : item->isInterestedInDragSource (sourceDescription, sourceComponent))
+							 : item->isInterestedInDragSource (dragSourceDetails))
 		{
 			// Check if we're trying to drag into an empty group item..
 			if (oldY > itemPos.getY() + itemPos.getHeight() / 4
@@ -57386,12 +57387,13 @@ TreeViewItem* TreeView::getInsertPosition (int& x, int& y, int& insertIndex,
 	return item->parentItem;
 }
 
-void TreeView::handleDrag (const StringArray& files, const String& sourceDescription, Component* sourceComponent, int x, int y)
+void TreeView::handleDrag (const StringArray& files, const SourceDetails& dragSourceDetails)
 {
-	const bool scrolled = viewport->autoScroll (x, y, 20, 10);
+	const bool scrolled = viewport->autoScroll (dragSourceDetails.localPosition.getX(),
+												dragSourceDetails.localPosition.getY(), 20, 10);
 
-	int insertIndex;
-	TreeViewItem* const item = getInsertPosition (x, y, insertIndex, files, sourceDescription, sourceComponent);
+	int insertIndex, x, y;
+	TreeViewItem* const item = getInsertPosition (x, y, insertIndex, files, dragSourceDetails);
 
 	if (item != nullptr)
 	{
@@ -57400,7 +57402,7 @@ void TreeView::handleDrag (const StringArray& files, const String& sourceDescrip
 			 || dragInsertPointHighlight->lastIndex != insertIndex)
 		{
 			if (files.size() > 0 ? item->isInterestedInFileDrag (files)
-								 : item->isInterestedInDragSource (sourceDescription, sourceComponent))
+								 : item->isInterestedInDragSource (dragSourceDetails))
 				showDragHighlight (item, insertIndex, x, y);
 			else
 				hideDragHighlight();
@@ -57412,12 +57414,12 @@ void TreeView::handleDrag (const StringArray& files, const String& sourceDescrip
 	}
 }
 
-void TreeView::handleDrop (const StringArray& files, const String& sourceDescription, Component* sourceComponent, int x, int y)
+void TreeView::handleDrop (const StringArray& files, const SourceDetails& dragSourceDetails)
 {
 	hideDragHighlight();
 
-	int insertIndex;
-	TreeViewItem* const item = getInsertPosition (x, y, insertIndex, files, sourceDescription, sourceComponent);
+	int insertIndex, x, y;
+	TreeViewItem* const item = getInsertPosition (x, y, insertIndex, files, dragSourceDetails);
 
 	if (item != nullptr)
 	{
@@ -57428,8 +57430,8 @@ void TreeView::handleDrop (const StringArray& files, const String& sourceDescrip
 		}
 		else
 		{
-			if (item->isInterestedInDragSource (sourceDescription, sourceComponent))
-				item->itemDropped (sourceDescription, sourceComponent, insertIndex);
+			if (item->isInterestedInDragSource (dragSourceDetails))
+				item->itemDropped (dragSourceDetails, insertIndex);
 		}
 	}
 }
@@ -57446,7 +57448,7 @@ void TreeView::fileDragEnter (const StringArray& files, int x, int y)
 
 void TreeView::fileDragMove (const StringArray& files, int x, int y)
 {
-	handleDrag (files, String::empty, 0, x, y);
+	handleDrag (files, SourceDetails (String::empty, 0, Point<int> (x, y)));
 }
 
 void TreeView::fileDragExit (const StringArray&)
@@ -57456,32 +57458,32 @@ void TreeView::fileDragExit (const StringArray&)
 
 void TreeView::filesDropped (const StringArray& files, int x, int y)
 {
-	handleDrop (files, String::empty, 0, x, y);
+	handleDrop (files, SourceDetails (String::empty, 0, Point<int> (x, y)));
 }
 
-bool TreeView::isInterestedInDragSource (const String& /*sourceDescription*/, Component* /*sourceComponent*/)
+bool TreeView::isInterestedInDragSource (const SourceDetails& /*dragSourceDetails*/)
 {
 	return true;
 }
 
-void TreeView::itemDragEnter (const String& sourceDescription, Component* sourceComponent, int x, int y)
+void TreeView::itemDragEnter (const SourceDetails& dragSourceDetails)
 {
-	itemDragMove (sourceDescription, sourceComponent, x, y);
+	itemDragMove (dragSourceDetails);
 }
 
-void TreeView::itemDragMove (const String& sourceDescription, Component* sourceComponent, int x, int y)
+void TreeView::itemDragMove (const SourceDetails& dragSourceDetails)
 {
-	handleDrag (StringArray(), sourceDescription, sourceComponent, x, y);
+	handleDrag (StringArray(), dragSourceDetails);
 }
 
-void TreeView::itemDragExit (const String& /*sourceDescription*/, Component* /*sourceComponent*/)
+void TreeView::itemDragExit (const SourceDetails& /*dragSourceDetails*/)
 {
 	hideDragHighlight();
 }
 
-void TreeView::itemDropped (const String& sourceDescription, Component* sourceComponent, int x, int y)
+void TreeView::itemDropped (const SourceDetails& dragSourceDetails)
 {
-	handleDrop (StringArray(), sourceDescription, sourceComponent, x, y);
+	handleDrop (StringArray(), dragSourceDetails);
 }
 
 enum TreeViewOpenness
@@ -57691,12 +57693,12 @@ void TreeViewItem::filesDropped (const StringArray& /*files*/, int /*insertIndex
 {
 }
 
-bool TreeViewItem::isInterestedInDragSource (const String& /*sourceDescription*/, Component* /*sourceComponent*/)
+bool TreeViewItem::isInterestedInDragSource (const DragAndDropTarget::SourceDetails& /*dragSourceDetails*/)
 {
 	return false;
 }
 
-void TreeViewItem::itemDropped (const String& /*sourceDescription*/, Component* /*sourceComponent*/, int /*insertIndex*/)
+void TreeViewItem::itemDropped (const DragAndDropTarget::SourceDetails& /*dragSourceDetails*/, int /*insertIndex*/)
 {
 }
 
@@ -62956,7 +62958,7 @@ void MultiDocumentPanelWindow::updateOrder()
 MultiDocumentPanel* MultiDocumentPanelWindow::getOwner() const noexcept
 {
 	// (unable to use the syntax findParentComponentOfClass <MultiDocumentPanel> () because of a VC6 compiler bug)
-	return findParentComponentOfClass ((MultiDocumentPanel*) 0);
+	return findParentComponentOfClass ((MultiDocumentPanel*) nullptr);
 }
 
 class MDITabbedComponentInternal   : public TabbedComponent
@@ -62974,7 +62976,7 @@ public:
 	void currentTabChanged (int, const String&)
 	{
 		// (unable to use the syntax findParentComponentOfClass <MultiDocumentPanel> () because of a VC6 compiler bug)
-		MultiDocumentPanel* const owner = findParentComponentOfClass ((MultiDocumentPanel*) 0);
+		MultiDocumentPanel* const owner = findParentComponentOfClass ((MultiDocumentPanel*) nullptr);
 
 		if (owner != nullptr)
 			owner->updateOrder();
@@ -70854,7 +70856,7 @@ private:
 			PopupMenu::ItemComponent* mic = dynamic_cast <PopupMenu::ItemComponent*> (c);
 
 			if (mic == nullptr && c != nullptr)
-				mic = c->findParentComponentOfClass ((PopupMenu::ItemComponent*) 0);
+				mic = c->findParentComponentOfClass ((PopupMenu::ItemComponent*) nullptr);
 
 			if (mic != currentChild
 				 && (isOver || (activeSubMenu == nullptr) || ! activeSubMenu->isVisible()))
@@ -71541,12 +71543,12 @@ public:
 						Component* const sourceComponent,
 						Component* const mouseDragSource_,
 						DragAndDropContainer* const o,
-						const Point<int>& imageOffset_)
-		: image (im),
-		  source (sourceComponent),
+						const Point<int>& imageOffset_,
+						ReferenceCountedObject* const customDataObject)
+		: sourceDetails (desc, sourceComponent, Point<int>(), customDataObject),
+		  image (im),
 		  mouseDragSource (mouseDragSource_),
 		  owner (o),
-		  dragDesc (desc),
 		  imageOffset (imageOffset_),
 		  hasCheckedForExternalDrag (false),
 		  drawImage (true)
@@ -71554,7 +71556,7 @@ public:
 		setSize (im.getWidth(), im.getHeight());
 
 		if (mouseDragSource == nullptr)
-			mouseDragSource = source;
+			mouseDragSource = sourceComponent;
 
 		mouseDragSource->addMouseListener (this, false);
 
@@ -71573,8 +71575,10 @@ public:
 		{
 			mouseDragSource->removeMouseListener (this);
 
-			if (getCurrentlyOver() != nullptr && getCurrentlyOver()->isInterestedInDragSource (dragDesc, source))
-				getCurrentlyOver()->itemDragExit (dragDesc, source);
+			DragAndDropTarget* const current = getCurrentlyOver();
+
+			if (current != nullptr && current->isInterestedInDragSource (sourceDetails))
+				current->itemDragExit (sourceDetails);
 		}
 	}
 
@@ -71604,15 +71608,15 @@ public:
 			hit = hit->getComponentAt (relPos.getX(), relPos.getY());
 		}
 
-		// (note: use a local copy of the dragDesc member in case the callback runs
+		// (note: use a local copy of this in case the callback runs
 		// a modal loop and deletes this object before the method completes)
-		const String dragDescLocal (dragDesc);
+		const DragAndDropTarget::SourceDetails details (sourceDetails);
 
 		while (hit != nullptr)
 		{
 			DragAndDropTarget* const ddt = dynamic_cast <DragAndDropTarget*> (hit);
 
-			if (ddt != nullptr && ddt->isInterestedInDragSource (dragDescLocal, source))
+			if (ddt != nullptr && ddt->isInterestedInDragSource (details))
 			{
 				relativePos = hit->getLocalPoint (nullptr, screenPos);
 				return ddt;
@@ -71646,13 +71650,13 @@ public:
 
 				setVisible (true);
 
-				if (dropAccepted || source == nullptr)
+				if (dropAccepted || sourceDetails.sourceComponent == nullptr)
 				{
 					Desktop::getInstance().getAnimator().fadeOut (this, 120);
 				}
 				else
 				{
-					const Point<int> target (source->localPointToGlobal (source->getLocalBounds().getCentre()));
+					const Point<int> target (sourceDetails.sourceComponent->localPointToGlobal (sourceDetails.sourceComponent->getLocalBounds().getCentre()));
 					const Point<int> ourCentre (localPointToGlobal (getLocalBounds().getCentre()));
 
 					Desktop::getInstance().getAnimator().animateComponent (this,
@@ -71667,13 +71671,14 @@ public:
 
 			if (dropAccepted && ddt != nullptr)
 			{
-				// (note: use a local copy of the dragDesc member in case the callback runs
+				// (note: use a local copy of this in case the callback runs
 				// a modal loop and deletes this object before the method completes)
-				const String dragDescLocal (dragDesc);
+				DragAndDropTarget::SourceDetails details (sourceDetails);
+				details.localPosition = relPos;
 
 				currentlyOverComp = nullptr;
 
-				ddt->itemDropped (dragDescLocal, source, relPos.getX(), relPos.getY());
+				ddt->itemDropped (details);
 			}
 
 			// careful - this object could now be deleted..
@@ -71682,9 +71687,9 @@ public:
 
 	void updateLocation (const bool canDoExternalDrag, const Point<int>& screenPos)
 	{
-		// (note: use a local copy of the dragDesc member in case the callback runs
-		// a modal loop and deletes this object before it returns)
-		const String dragDescLocal (dragDesc);
+		// (note: use a local copy of this in case a callback runs a modal loop and deletes
+		// this object before it returns)
+		DragAndDropTarget::SourceDetails details (sourceDetails);
 
 		Point<int> newPos (screenPos + imageOffset);
 
@@ -71696,29 +71701,41 @@ public:
 			setTopLeftPosition (newPos.getX(), newPos.getY());
 
 			Point<int> relPos;
-			DragAndDropTarget* const ddt = findTarget (screenPos, relPos);
-			Component* ddtComp = dynamic_cast <Component*> (ddt);
+			DragAndDropTarget* const newTarget = findTarget (screenPos, relPos);
+			Component* newTargetComp = dynamic_cast <Component*> (newTarget);
 
-			drawImage = (ddt == nullptr) || ddt->shouldDrawDragImageWhenOver();
+			drawImage = (newTarget == nullptr) || newTarget->shouldDrawDragImageWhenOver();
 
-			if (ddtComp != currentlyOverComp)
+			if (newTargetComp != currentlyOverComp)
 			{
-				if (currentlyOverComp != nullptr && source != nullptr
-					  && getCurrentlyOver()->isInterestedInDragSource (dragDescLocal, source))
+				DragAndDropTarget* const lastTarget = getCurrentlyOver();
+
+				if (lastTarget != nullptr && details.sourceComponent != nullptr
+					  && lastTarget->isInterestedInDragSource (details))
+					lastTarget->itemDragExit (details);
+
+				currentlyOverComp = newTargetComp;
+
+				if (newTarget != nullptr)
 				{
-					getCurrentlyOver()->itemDragExit (dragDescLocal, source);
+					details.localPosition = relPos;
+
+					if (newTarget->isInterestedInDragSource (details))
+						newTarget->itemDragEnter (details);
 				}
+			}
 
-				currentlyOverComp = ddtComp;
+			{
+				DragAndDropTarget* const target = getCurrentlyOver();
+				if (target != nullptr)
+				{
+					details.localPosition = relPos;
 
-				if (ddt != nullptr && ddt->isInterestedInDragSource (dragDescLocal, source))
-					ddt->itemDragEnter (dragDescLocal, source, relPos.getX(), relPos.getY());
+					if (target->isInterestedInDragSource (details))
+						target->itemDragMove (details);
+				}
 			}
 
-			DragAndDropTarget* target = getCurrentlyOver();
-			if (target != nullptr && target->isInterestedInDragSource (dragDescLocal, source))
-				target->itemDragMove (dragDescLocal, source, relPos.getX(), relPos.getY());
-
 			if (getCurrentlyOver() == nullptr && canDoExternalDrag && ! hasCheckedForExternalDrag)
 			{
 				if (Desktop::getInstance().findComponentAt (screenPos) == nullptr)
@@ -71727,7 +71744,7 @@ public:
 					StringArray files;
 					bool canMoveFiles = false;
 
-					if (owner->shouldDropFilesWhenDraggedExternally (dragDescLocal, source, files, canMoveFiles)
+					if (owner->shouldDropFilesWhenDraggedExternally (details, files, canMoveFiles)
 						 && files.size() > 0)
 					{
 						WeakReference<Component> thisWeakRef (this);
@@ -71752,7 +71769,7 @@ public:
 
 	void timerCallback()
 	{
-		if (source == nullptr)
+		if (sourceDetails.sourceComponent == nullptr)
 		{
 			delete this;
 		}
@@ -71766,8 +71783,8 @@ public:
 	}
 
 private:
+	DragAndDropTarget::SourceDetails sourceDetails;
 	Image image;
-	WeakReference<Component> source;
 	WeakReference<Component> mouseDragSource;
 	DragAndDropContainer* const owner;
 
@@ -71777,7 +71794,6 @@ private:
 		return dynamic_cast <DragAndDropTarget*> (currentlyOverComp.get());
 	}
 
-	String dragDesc;
 	const Point<int> imageOffset;
 	bool hasCheckedForExternalDrag, drawImage;
 
@@ -71797,7 +71813,8 @@ void DragAndDropContainer::startDragging (const String& sourceDescription,
 										  Component* sourceComponent,
 										  const Image& dragImage_,
 										  const bool allowDraggingToExternalWindows,
-										  const Point<int>* imageOffsetFromMouse)
+										  const Point<int>* imageOffsetFromMouse,
+										  ReferenceCountedObject* customDataObject)
 {
 	Image dragImage (dragImage_);
 
@@ -71866,7 +71883,8 @@ void DragAndDropContainer::startDragging (const String& sourceDescription,
 		}
 
 		dragImageComponent = new DragImageComponent (dragImage, sourceDescription, sourceComponent,
-													 draggingSource->getComponentUnderMouse(), this, imageOffset);
+													 draggingSource->getComponentUnderMouse(), this,
+													 imageOffset, customDataObject);
 
 		currentDragDesc = sourceDescription;
 
@@ -71908,42 +71926,31 @@ const String DragAndDropContainer::getCurrentDragDescription() const
 
 DragAndDropContainer* DragAndDropContainer::findParentDragContainerFor (Component* c)
 {
-	return c == nullptr ? nullptr : c->findParentComponentOfClass ((DragAndDropContainer*) 0);
+	return c == nullptr ? nullptr : c->findParentComponentOfClass ((DragAndDropContainer*) nullptr);
 }
 
-bool DragAndDropContainer::shouldDropFilesWhenDraggedExternally (const String&, Component*, StringArray&, bool&)
+bool DragAndDropContainer::shouldDropFilesWhenDraggedExternally (const DragAndDropTarget::SourceDetails&, StringArray&, bool&)
 {
 	return false;
 }
 
-void DragAndDropTarget::itemDragEnter (const String&, Component*, int, int)
-{
-}
-
-void DragAndDropTarget::itemDragMove (const String&, Component*, int, int)
-{
-}
-
-void DragAndDropTarget::itemDragExit (const String&, Component*)
+DragAndDropTarget::SourceDetails::SourceDetails (const String& description_, Component* sourceComponent_,
+												 const Point<int>& localPosition_, ReferenceCountedObject* const customDataObject_) noexcept
+	: description (description_),
+	  sourceComponent (sourceComponent_),
+	  localPosition (localPosition_),
+	  customDataObject (customDataObject_)
 {
 }
 
-bool DragAndDropTarget::shouldDrawDragImageWhenOver()
-{
-	return true;
-}
-
-void FileDragAndDropTarget::fileDragEnter (const StringArray&, int, int)
-{
-}
-
-void FileDragAndDropTarget::fileDragMove (const StringArray&, int, int)
-{
-}
+void DragAndDropTarget::itemDragEnter (const SourceDetails&)  {}
+void DragAndDropTarget::itemDragMove  (const SourceDetails&)  {}
+void DragAndDropTarget::itemDragExit  (const SourceDetails&)  {}
+bool DragAndDropTarget::shouldDrawDragImageWhenOver()	 { return true; }
 
-void FileDragAndDropTarget::fileDragExit (const StringArray&)
-{
-}
+void FileDragAndDropTarget::fileDragEnter (const StringArray&, int, int)  {}
+void FileDragAndDropTarget::fileDragMove  (const StringArray&, int, int)  {}
+void FileDragAndDropTarget::fileDragExit  (const StringArray&)		{}
 
 END_JUCE_NAMESPACE
 /*** End of inlined file: juce_DragAndDropContainer.cpp ***/
@@ -73115,7 +73122,7 @@ public:
 			for (int i = propertyComps.size(); --i >= 0;)
 				propertyComps.getUnchecked(i)->setVisible (open);
 
-			PropertyPanel* const pp = findParentComponentOfClass ((PropertyPanel*) 0);
+			PropertyPanel* const pp = findParentComponentOfClass ((PropertyPanel*) nullptr);
 
 			if (pp != nullptr)
 				pp->resized();
@@ -79771,22 +79778,35 @@ void TooltipWindow::showFor (const String& tip)
 	tipShowing = tip;
 
 	Point<int> mousePos (Desktop::getMousePosition());
+	Rectangle<int> parentArea;
 
 	if (getParentComponent() != nullptr)
+	{
 		mousePos = getParentComponent()->getLocalPoint (nullptr, mousePos);
+		parentArea = getParentComponent()->getLocalBounds();
+	}
+	else
+	{
+		parentArea = Desktop::getInstance().getMonitorAreaContaining (mousePos);
+	}
 
-	int x, y, w, h;
+	int w, h;
 	getLookAndFeel().getTooltipSize (tip, w, h);
 
-	if (mousePos.getX() > getParentWidth() / 2)
-		x = mousePos.getX() - (w + 12);
+	int x = mousePos.getX();
+	if (x > parentArea.getCentreX())
+		x -= (w + 12);
 	else
-		x = mousePos.getX() + 24;
+		x += 24;
 
-	if (mousePos.getY() > getParentHeight() / 2)
-		y = mousePos.getY() - (h + 6);
+	int y = mousePos.getY();
+	if (y > parentArea.getCentreY())
+		y -= (h + 6);
 	else
-		y = mousePos.getY() + 6;
+		y += 6;
+
+	x = jlimit (parentArea.getX(), parentArea.getRight() - w, x);
+	y = jlimit (parentArea.getY(), parentArea.getBottom() - h, y);
 
 	setBounds (x, y, w, h);
 	setVisible (true);
@@ -79915,7 +79935,7 @@ public:
 
 			if (tlw == nullptr && c != nullptr)
 				// (unable to use the syntax findParentComponentOfClass <TopLevelWindow> () because of a VC6 compiler bug)
-				tlw = c->findParentComponentOfClass ((TopLevelWindow*) 0);
+				tlw = c->findParentComponentOfClass ((TopLevelWindow*) nullptr);
 
 			if (tlw != nullptr)
 				active = tlw;

juce_amalgamated.h

@@ -50619,16 +50619,42 @@ public:
 	/** Destructor. */
 	virtual ~DragAndDropTarget()  {}
 
+	/** Contains details about the source of a drag-and-drop operation.
+		The contents of this
+	*/
+	class JUCE_API  SourceDetails
+	{
+	public:
+		/** Creates a SourceDetails object from its various settings. */
+		SourceDetails (const String& description, Component* sourceComponent,
+					   const Point<int>& localPosition, ReferenceCountedObject* customDataObject = nullptr) noexcept;
+
+		/** A descriptor string - this is set DragAndDropContainer::startDragging(). */
+		String description;
+
+		/** The component from the drag operation was started. */
+		WeakReference<Component> sourceComponent;
+
+		/** The local position of the mouse, relative to the target component.
+			Note that for calls such as isInterestedInDragSource(), this may be a null position.
+		*/
+		Point<int> localPosition;
+
+		/** A pointer to a user-supplied object which contains some kind of data which is relevant to
+			the specific classes which are being used. Make sure that you check the type of this object,
+			and safely dynamic_cast it to your required type.
+		*/
+		ReferenceCountedObjectPtr<ReferenceCountedObject> customDataObject;
+	};
+
 	/** Callback to check whether this target is interested in the type of object being
 		dragged.
 
-		@param sourceDescription	the description string passed into DragAndDropContainer::startDragging()
-		@param sourceComponent	  the component that was passed into DragAndDropContainer::startDragging()
+		@param dragSourceDetails	contains information about the source of the drag operation.
 		@returns			true if this component wants to receive the other callbacks regarging this
 									type of object; if it returns false, no other callbacks will be made.
 	*/
-	virtual bool isInterestedInDragSource (const String& sourceDescription,
-										   Component* sourceComponent) = 0;
+	virtual bool isInterestedInDragSource (const SourceDetails& dragSourceDetails) = 0;
 
 	/** Callback to indicate that something is being dragged over this component.
 
@@ -50638,15 +50664,10 @@ public:
 		Use this callback as a trigger to make your component repaint itself to give the
 		user feedback about whether the item can be dropped here or not.
 
-		@param sourceDescription	the description string passed into DragAndDropContainer::startDragging()
-		@param sourceComponent	  the component that was passed into DragAndDropContainer::startDragging()
-		@param x			the mouse x position, relative to this component
-		@param y			the mouse y position, relative to this component
+		@param dragSourceDetails	contains information about the source of the drag operation.
 		@see itemDragExit
 	*/
-	virtual void itemDragEnter (const String& sourceDescription,
-								Component* sourceComponent,
-								int x, int y);
+	virtual void itemDragEnter (const SourceDetails& dragSourceDetails);
 
 	/** Callback to indicate that the user is dragging something over this component.
 
@@ -50654,14 +50675,9 @@ public:
 		something. Normally overriding itemDragEnter() and itemDragExit() are enough, but
 		this lets you know what happens in-between.
 
-		@param sourceDescription	the description string passed into DragAndDropContainer::startDragging()
-		@param sourceComponent	  the component that was passed into DragAndDropContainer::startDragging()
-		@param x			the mouse x position, relative to this component
-		@param y			the mouse y position, relative to this component
+		@param dragSourceDetails	contains information about the source of the drag operation.
 	*/
-	virtual void itemDragMove (const String& sourceDescription,
-							   Component* sourceComponent,
-							   int x, int y);
+	virtual void itemDragMove (const SourceDetails& dragSourceDetails);
 
 	/** Callback to indicate that something has been dragged off the edge of this component.
 
@@ -50671,12 +50687,10 @@ public:
 		If you've used itemDragEnter() to repaint your component and give feedback, use this
 		as a signal to repaint it in its normal state.
 
-		@param sourceDescription	the description string passed into DragAndDropContainer::startDragging()
-		@param sourceComponent	  the component that was passed into DragAndDropContainer::startDragging()
+		@param dragSourceDetails	contains information about the source of the drag operation.
 		@see itemDragEnter
 	*/
-	virtual void itemDragExit (const String& sourceDescription,
-							   Component* sourceComponent);
+	virtual void itemDragExit (const SourceDetails& dragSourceDetails);
 
 	/** Callback to indicate that the user has dropped something onto this component.
 
@@ -50686,14 +50700,9 @@ public:
 		Note that after this is called, the itemDragExit method may not be called, so you should
 		clean up in here if there's anything you need to do when the drag finishes.
 
-		@param sourceDescription	the description string passed into DragAndDropContainer::startDragging()
-		@param sourceComponent	  the component that was passed into DragAndDropContainer::startDragging()
-		@param x			the mouse x position, relative to this component
-		@param y			the mouse y position, relative to this component
+		@param dragSourceDetails	contains information about the source of the drag operation.
 	*/
-	virtual void itemDropped (const String& sourceDescription,
-							  Component* sourceComponent,
-							  int x, int y) = 0;
+	virtual void itemDropped (const SourceDetails& dragSourceDetails) = 0;
 
 	/** Overriding this allows the target to tell the drag container whether to
 		draw the drag image while the cursor is over it.
@@ -50702,6 +50711,16 @@ public:
 		image will not be shown when the cursor is over this target.
 	*/
 	virtual bool shouldDrawDragImageWhenOver();
+
+private:
+   #if JUCE_CATCH_DEPRECATED_CODE_MISUSE
+	// The parameters for these methods have changed - please update your code!
+	virtual void isInterestedInDragSource (const String&, Component*) {}
+	virtual int itemDragEnter (const String&, Component*, int, int) { return 0; }
+	virtual int itemDragMove (const String&, Component*, int, int) { return 0; }
+	virtual int itemDragExit (const String&, Component*) { return 0; }
+	virtual int itemDropped (const String&, Component*, int, int) { return 0; }
+   #endif
 };
 
 #endif   // __JUCE_DRAGANDDROPTARGET_JUCEHEADER__
@@ -50749,10 +50768,9 @@ public:
 		findParentDragContainerFor() is a handy method to call to find the
 		drag container to use for a component.
 
-		@param sourceDescription	a string to use as the description of the thing being
-									dragged - this will be passed to the objects that might be
-									dropped-onto so they can decide if they want to handle it or
-									not
+		@param sourceDescription	a string to use as the description of the thing being dragged - this
+									will be passed to the objects that might be dropped-onto so they can
+									decide whether they want to handle it
 		@param sourceComponent	  the component that is being dragged
 		@param dragImage		the image to drag around underneath the mouse. If this is a null image,
 									a snapshot of the sourceComponent will be used instead.
@@ -50763,12 +50781,16 @@ public:
 									at which the image should be drawn from the mouse. If it isn't
 									specified, then the image will be centred around the mouse. If
 									an image hasn't been passed-in, this will be ignored.
+		@param customDataObject	 Any kind of reference-counted object which you want to have passed to
+									the target component. A pointer to this object will be made available
+									to the targets in the DragAndDropTarget::SourceDetails class.
 	*/
 	void startDragging (const String& sourceDescription,
 						Component* sourceComponent,
 						const Image& dragImage = Image::null,
 						bool allowDraggingToOtherJuceWindows = false,
-						const Point<int>* imageOffsetFromMouse = nullptr);
+						const Point<int>* imageOffsetFromMouse = nullptr,
+						ReferenceCountedObject* customDataObject = nullptr);
 
 	/** Returns true if something is currently being dragged. */
 	bool isDragAndDropActive() const;
@@ -50842,8 +50864,7 @@ protected:
 											method)
 		@see performExternalDragDropOfFiles
 	*/
-	virtual bool shouldDropFilesWhenDraggedExternally (const String& dragSourceDescription,
-													   Component* dragSourceComponent,
+	virtual bool shouldDropFilesWhenDraggedExternally (const DragAndDropTarget::SourceDetails& sourceDetails,
 													   StringArray& files,
 													   bool& canMoveFiles);
 
@@ -50853,6 +50874,8 @@ private:
 	ScopedPointer <Component> dragImageComponent;
 	String currentDragDesc;
 
+	JUCE_DEPRECATED (virtual bool shouldDropFilesWhenDraggedExternally (const String&, Component*, StringArray&, bool&)) { return false; }
+
 	JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (DragAndDropContainer);
 };
 
@@ -51100,13 +51123,13 @@ public:
 	/** @internal */
 	void mouseDown (const MouseEvent&);
 	/** @internal */
-	bool isInterestedInDragSource (const String&, Component*);
+	bool isInterestedInDragSource (const SourceDetails&);
 	/** @internal */
-	void itemDragMove (const String&, Component*, int, int);
+	void itemDragMove (const SourceDetails&);
 	/** @internal */
-	void itemDragExit (const String&, Component*);
+	void itemDragExit (const SourceDetails&);
 	/** @internal */
-	void itemDropped (const String&, Component*, int, int);
+	void itemDropped (const SourceDetails&);
 	/** @internal */
 	void updateAllItemPositions (bool animate);
 	/** @internal */
@@ -54388,7 +54411,7 @@ public:
 		To respond to drag-and-drop of files from external applications, see isInterestedInFileDrag().
 		@see DragAndDropTarget::isInterestedInDragSource, itemDropped
 	*/
-	virtual bool isInterestedInDragSource (const String& sourceDescription, Component* sourceComponent);
+	virtual bool isInterestedInDragSource (const DragAndDropTarget::SourceDetails& dragSourceDetails);
 
 	/** When a things are dropped into this item, this callback is invoked.
 
@@ -54396,7 +54419,7 @@ public:
 		The insertIndex value indicates where in the list of sub-items the new items should be placed.
 		@see isInterestedInDragSource, DragAndDropTarget::itemDropped
 	*/
-	virtual void itemDropped (const String& sourceDescription, Component* sourceComponent, int insertIndex);
+	virtual void itemDropped (const DragAndDropTarget::SourceDetails& dragSourceDetails, int insertIndex);
 
 	/** Sets a flag to indicate that the item wants to be allowed
 		to draw all the way across to the left edge of the treeview.
@@ -54523,6 +54546,12 @@ private:
 	TreeViewItem* getNextVisibleItem (bool recurse) const noexcept;
 	TreeViewItem* findItemFromIdentifierString (const String& identifierString);
 
+   #if JUCE_CATCH_DEPRECATED_CODE_MISUSE
+	// The parameters for these methods have changed - please update your code!
+	virtual void isInterestedInDragSource (const String&, Component*) {}
+	virtual int itemDropped (const String&, Component*, int) { return 0; }
+   #endif
+
 	JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (TreeViewItem);
 };
 
@@ -54761,15 +54790,15 @@ public:
 	/** @internal */
 	void filesDropped (const StringArray& files, int x, int y);
 	/** @internal */
-	bool isInterestedInDragSource (const String& sourceDescription, Component* sourceComponent);
+	bool isInterestedInDragSource (const SourceDetails&);
 	/** @internal */
-	void itemDragEnter (const String& sourceDescription, Component* sourceComponent, int x, int y);
+	void itemDragEnter (const SourceDetails&);
 	/** @internal */
-	void itemDragMove (const String& sourceDescription, Component* sourceComponent, int x, int y);
+	void itemDragMove (const SourceDetails&);
 	/** @internal */
-	void itemDragExit (const String& sourceDescription, Component* sourceComponent);
+	void itemDragExit (const SourceDetails&);
 	/** @internal */
-	void itemDropped (const String& sourceDescription, Component* sourceComponent, int x, int y);
+	void itemDropped (const SourceDetails&);
 
 private:
 	friend class TreeViewItem;
@@ -54798,11 +54827,10 @@ private:
 	void updateButtonUnderMouse (const MouseEvent& e);
 	void showDragHighlight (TreeViewItem* item, int insertIndex, int x, int y) noexcept;
 	void hideDragHighlight() noexcept;
-	void handleDrag (const StringArray& files, const String& sourceDescription, Component* sourceComponent, int x, int y);
-	void handleDrop (const StringArray& files, const String& sourceDescription, Component* sourceComponent, int x, int y);
+	void handleDrag (const StringArray& files, const SourceDetails&);
+	void handleDrop (const StringArray& files, const SourceDetails&);
 	TreeViewItem* getInsertPosition (int& x, int& y, int& insertIndex,
-									 const StringArray& files, const String& sourceDescription,
-									 Component* sourceComponent) const noexcept;
+									 const StringArray& files, const SourceDetails&) const noexcept;
 
 	JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (TreeView);
 };
@@ -64832,7 +64860,7 @@ public:
 		the DialogWindow that is created. To find a pointer to this window from your
 		contentComponent, you can do something like this:
 		@code
-		Dialogwindow* dw = contentComponent->findParentComponentOfClass ((DialogWindow*) 0);
+		Dialogwindow* dw = contentComponent->findParentComponentOfClass ((DialogWindow*) nullptr);
 
 		if (dw != nullptr)
 			dw->exitModalState (1234);
@@ -64875,7 +64903,7 @@ public:
 		the DialogWindow that is created. To find a pointer to this window from your
 		contentComponent, you can do something like this:
 		@code
-		Dialogwindow* dw = contentComponent->findParentComponentOfClass ((DialogWindow*) 0);
+		Dialogwindow* dw = contentComponent->findParentComponentOfClass ((DialogWindow*) nullptr);
 
 		if (dw != nullptr)
 			dw->exitModalState (1234);

src/application/juce_ApplicationCommandManager.cpp

@@ -244,7 +244,7 @@ ApplicationCommandTarget* ApplicationCommandManager::findTargetForComponent (Com
 
     if (target == nullptr && c != nullptr)
         // (unable to use the syntax findParentComponentOfClass <ApplicationCommandTarget> () because of a VC6 compiler bug)
-        target = c->findParentComponentOfClass ((ApplicationCommandTarget*) 0);
+        target = c->findParentComponentOfClass ((ApplicationCommandTarget*) nullptr);
 
     return target;
 }

src/application/juce_ApplicationCommandTarget.cpp

@@ -74,7 +74,7 @@ ApplicationCommandTarget* ApplicationCommandTarget::findFirstTargetParentCompone
 
     if (c != nullptr)
         // (unable to use the syntax findParentComponentOfClass <ApplicationCommandTarget> () because of a VC6 compiler bug)
-        return c->findParentComponentOfClass ((ApplicationCommandTarget*) 0);
+        return c->findParentComponentOfClass ((ApplicationCommandTarget*) nullptr);
 
     return nullptr;
 }

src/containers/juce_Variant.cpp

@@ -464,7 +464,7 @@ const var var::invoke (const var& targetObject, const var* arguments, int numArg
 
 const var var::call (const Identifier& method) const
 {
-    return invoke (method, 0, 0);
+    return invoke (method, nullptr, 0);
 }
 
 const var var::call (const Identifier& method, const var& arg1) const

src/core/juce_StandardHeader.h

@@ -33,7 +33,7 @@
 */
 #define JUCE_MAJOR_VERSION      1
 #define JUCE_MINOR_VERSION      53
-#define JUCE_BUILDNUMBER        73
+#define JUCE_BUILDNUMBER        74
 
 /** Current Juce version number.
 

src/gui/components/controls/juce_Toolbar.cpp

@@ -563,15 +563,14 @@ void Toolbar::buttonClicked (Button*)
 }
 
 //==============================================================================
-bool Toolbar::isInterestedInDragSource (const String& sourceDescription,
-                                        Component* /*sourceComponent*/)
+bool Toolbar::isInterestedInDragSource (const SourceDetails& dragSourceDetails)
 {
-    return sourceDescription == toolbarDragDescriptor && isEditingActive;
+    return dragSourceDetails.description == toolbarDragDescriptor && isEditingActive;
 }
 
-void Toolbar::itemDragMove (const String&, Component* sourceComponent, int x, int y)
+void Toolbar::itemDragMove (const SourceDetails& dragSourceDetails)
 {
-    ToolbarItemComponent* const tc = dynamic_cast <ToolbarItemComponent*> (sourceComponent);
+    ToolbarItemComponent* const tc = dynamic_cast <ToolbarItemComponent*> (dragSourceDetails.sourceComponent.get());
 
     if (tc != nullptr)
     {
@@ -579,7 +578,7 @@ void Toolbar::itemDragMove (const String&, Component* sourceComponent, int x, in
         {
             if (tc->getEditingMode() == ToolbarItemComponent::editableOnPalette)
             {
-                ToolbarItemPalette* const palette = tc->findParentComponentOfClass ((ToolbarItemPalette*) 0);
+                ToolbarItemPalette* const palette = tc->findParentComponentOfClass ((ToolbarItemPalette*) nullptr);
 
                 if (palette != nullptr)
                     palette->replaceComponent (tc);
@@ -599,7 +598,8 @@ void Toolbar::itemDragMove (const String&, Component* sourceComponent, int x, in
             const int currentIndex = items.indexOf (tc);
             int newIndex = currentIndex;
 
-            const int dragObjectLeft = vertical ? (y - tc->dragOffsetY) : (x - tc->dragOffsetX);
+            const int dragObjectLeft = vertical ? (dragSourceDetails.localPosition.getY() - tc->dragOffsetY)
+                                                : (dragSourceDetails.localPosition.getX() - tc->dragOffsetX);
             const int dragObjectRight = dragObjectLeft + (vertical ? tc->getHeight() : tc->getWidth());
 
             const Rectangle<int> current (Desktop::getInstance().getAnimator()
@@ -641,9 +641,9 @@ void Toolbar::itemDragMove (const String&, Component* sourceComponent, int x, in
     }
 }
 
-void Toolbar::itemDragExit (const String&, Component* sourceComponent)
+void Toolbar::itemDragExit (const SourceDetails& dragSourceDetails)
 {
-    ToolbarItemComponent* const tc = dynamic_cast <ToolbarItemComponent*> (sourceComponent);
+    ToolbarItemComponent* const tc = dynamic_cast <ToolbarItemComponent*> (dragSourceDetails.sourceComponent.get());
 
     if (tc != nullptr && isParentOf (tc))
     {
@@ -653,9 +653,9 @@ void Toolbar::itemDragExit (const String&, Component* sourceComponent)
     }
 }
 
-void Toolbar::itemDropped (const String&, Component* sourceComponent, int, int)
+void Toolbar::itemDropped (const SourceDetails& dragSourceDetails)
 {
-    ToolbarItemComponent* const tc = dynamic_cast <ToolbarItemComponent*> (sourceComponent);
+    ToolbarItemComponent* const tc = dynamic_cast <ToolbarItemComponent*> (dragSourceDetails.sourceComponent.get());
 
     if (tc != nullptr)
         tc->setState (Button::buttonNormal);
@@ -806,7 +806,7 @@ private:
         {
             Colour background;
 
-            DialogWindow* const dw = findParentComponentOfClass ((DialogWindow*) 0);
+            DialogWindow* const dw = findParentComponentOfClass ((DialogWindow*) nullptr);
 
             if (dw != nullptr)
                 background = dw->getBackgroundColour();

src/gui/components/controls/juce_Toolbar.h

@@ -279,13 +279,13 @@ public:
     /** @internal */
     void mouseDown (const MouseEvent&);
     /** @internal */
-    bool isInterestedInDragSource (const String&, Component*);
+    bool isInterestedInDragSource (const SourceDetails&);
     /** @internal */
-    void itemDragMove (const String&, Component*, int, int);
+    void itemDragMove (const SourceDetails&);
     /** @internal */
-    void itemDragExit (const String&, Component*);
+    void itemDragExit (const SourceDetails&);
     /** @internal */
-    void itemDropped (const String&, Component*, int, int);
+    void itemDropped (const SourceDetails&);
     /** @internal */
     void updateAllItemPositions (bool animate);
     /** @internal */

src/gui/components/controls/juce_TreeView.cpp

@@ -943,9 +943,10 @@ void TreeView::hideDragHighlight() noexcept
 }
 
 TreeViewItem* TreeView::getInsertPosition (int& x, int& y, int& insertIndex,
-                                           const StringArray& files, const String& sourceDescription,
-                                           Component* sourceComponent) const noexcept
+                                           const StringArray& files, const SourceDetails& dragSourceDetails) const noexcept
 {
+    x = dragSourceDetails.localPosition.getX();
+    y = dragSourceDetails.localPosition.getY();
     insertIndex = 0;
     TreeViewItem* item = getItemAt (y);
 
@@ -960,7 +961,7 @@ TreeViewItem* TreeView::getInsertPosition (int& x, int& y, int& insertIndex,
     if (item->getNumSubItems() == 0 || ! item->isOpen())
     {
         if (files.size() > 0 ? item->isInterestedInFileDrag (files)
-                             : item->isInterestedInDragSource (sourceDescription, sourceComponent))
+                             : item->isInterestedInDragSource (dragSourceDetails))
         {
             // Check if we're trying to drag into an empty group item..
             if (oldY > itemPos.getY() + itemPos.getHeight() / 4
@@ -996,12 +997,13 @@ TreeViewItem* TreeView::getInsertPosition (int& x, int& y, int& insertIndex,
     return item->parentItem;
 }
 
-void TreeView::handleDrag (const StringArray& files, const String& sourceDescription, Component* sourceComponent, int x, int y)
+void TreeView::handleDrag (const StringArray& files, const SourceDetails& dragSourceDetails)
 {
-    const bool scrolled = viewport->autoScroll (x, y, 20, 10);
+    const bool scrolled = viewport->autoScroll (dragSourceDetails.localPosition.getX(),
+                                                dragSourceDetails.localPosition.getY(), 20, 10);
 
-    int insertIndex;
-    TreeViewItem* const item = getInsertPosition (x, y, insertIndex, files, sourceDescription, sourceComponent);
+    int insertIndex, x, y;
+    TreeViewItem* const item = getInsertPosition (x, y, insertIndex, files, dragSourceDetails);
 
     if (item != nullptr)
     {
@@ -1010,7 +1012,7 @@ void TreeView::handleDrag (const StringArray& files, const String& sourceDescrip
              || dragInsertPointHighlight->lastIndex != insertIndex)
         {
             if (files.size() > 0 ? item->isInterestedInFileDrag (files)
-                                 : item->isInterestedInDragSource (sourceDescription, sourceComponent))
+                                 : item->isInterestedInDragSource (dragSourceDetails))
                 showDragHighlight (item, insertIndex, x, y);
             else
                 hideDragHighlight();
@@ -1022,12 +1024,12 @@ void TreeView::handleDrag (const StringArray& files, const String& sourceDescrip
     }
 }
 
-void TreeView::handleDrop (const StringArray& files, const String& sourceDescription, Component* sourceComponent, int x, int y)
+void TreeView::handleDrop (const StringArray& files, const SourceDetails& dragSourceDetails)
 {
     hideDragHighlight();
 
-    int insertIndex;
-    TreeViewItem* const item = getInsertPosition (x, y, insertIndex, files, sourceDescription, sourceComponent);
+    int insertIndex, x, y;
+    TreeViewItem* const item = getInsertPosition (x, y, insertIndex, files, dragSourceDetails);
 
     if (item != nullptr)
     {
@@ -1038,8 +1040,8 @@ void TreeView::handleDrop (const StringArray& files, const String& sourceDescrip
         }
         else
         {
-            if (item->isInterestedInDragSource (sourceDescription, sourceComponent))
-                item->itemDropped (sourceDescription, sourceComponent, insertIndex);
+            if (item->isInterestedInDragSource (dragSourceDetails))
+                item->itemDropped (dragSourceDetails, insertIndex);
         }
     }
 }
@@ -1057,7 +1059,7 @@ void TreeView::fileDragEnter (const StringArray& files, int x, int y)
 
 void TreeView::fileDragMove (const StringArray& files, int x, int y)
 {
-    handleDrag (files, String::empty, 0, x, y);
+    handleDrag (files, SourceDetails (String::empty, 0, Point<int> (x, y)));
 }
 
 void TreeView::fileDragExit (const StringArray&)
@@ -1067,32 +1069,32 @@ void TreeView::fileDragExit (const StringArray&)
 
 void TreeView::filesDropped (const StringArray& files, int x, int y)
 {
-    handleDrop (files, String::empty, 0, x, y);
+    handleDrop (files, SourceDetails (String::empty, 0, Point<int> (x, y)));
 }
 
-bool TreeView::isInterestedInDragSource (const String& /*sourceDescription*/, Component* /*sourceComponent*/)
+bool TreeView::isInterestedInDragSource (const SourceDetails& /*dragSourceDetails*/)
 {
     return true;
 }
 
-void TreeView::itemDragEnter (const String& sourceDescription, Component* sourceComponent, int x, int y)
+void TreeView::itemDragEnter (const SourceDetails& dragSourceDetails)
 {
-    itemDragMove (sourceDescription, sourceComponent, x, y);
+    itemDragMove (dragSourceDetails);
 }
 
-void TreeView::itemDragMove (const String& sourceDescription, Component* sourceComponent, int x, int y)
+void TreeView::itemDragMove (const SourceDetails& dragSourceDetails)
 {
-    handleDrag (StringArray(), sourceDescription, sourceComponent, x, y);
+    handleDrag (StringArray(), dragSourceDetails);
 }
 
-void TreeView::itemDragExit (const String& /*sourceDescription*/, Component* /*sourceComponent*/)
+void TreeView::itemDragExit (const SourceDetails& /*dragSourceDetails*/)
 {
     hideDragHighlight();
 }
 
-void TreeView::itemDropped (const String& sourceDescription, Component* sourceComponent, int x, int y)
+void TreeView::itemDropped (const SourceDetails& dragSourceDetails)
 {
-    handleDrop (StringArray(), sourceDescription, sourceComponent, x, y);
+    handleDrop (StringArray(), dragSourceDetails);
 }
 
 //==============================================================================
@@ -1303,12 +1305,12 @@ void TreeViewItem::filesDropped (const StringArray& /*files*/, int /*insertIndex
 {
 }
 
-bool TreeViewItem::isInterestedInDragSource (const String& /*sourceDescription*/, Component* /*sourceComponent*/)
+bool TreeViewItem::isInterestedInDragSource (const DragAndDropTarget::SourceDetails& /*dragSourceDetails*/)
 {
     return false;
 }
 
-void TreeViewItem::itemDropped (const String& /*sourceDescription*/, Component* /*sourceComponent*/, int /*insertIndex*/)
+void TreeViewItem::itemDropped (const DragAndDropTarget::SourceDetails& /*dragSourceDetails*/, int /*insertIndex*/)
 {
 }
 

src/gui/components/controls/juce_TreeView.h

@@ -384,7 +384,7 @@ public:
         To respond to drag-and-drop of files from external applications, see isInterestedInFileDrag().
         @see DragAndDropTarget::isInterestedInDragSource, itemDropped
     */
-    virtual bool isInterestedInDragSource (const String& sourceDescription, Component* sourceComponent);
+    virtual bool isInterestedInDragSource (const DragAndDropTarget::SourceDetails& dragSourceDetails);
 
     /** When a things are dropped into this item, this callback is invoked.
 
@@ -392,7 +392,7 @@ public:
         The insertIndex value indicates where in the list of sub-items the new items should be placed.
         @see isInterestedInDragSource, DragAndDropTarget::itemDropped
     */
-    virtual void itemDropped (const String& sourceDescription, Component* sourceComponent, int insertIndex);
+    virtual void itemDropped (const DragAndDropTarget::SourceDetails& dragSourceDetails, int insertIndex);
 
     //==============================================================================
     /** Sets a flag to indicate that the item wants to be allowed
@@ -523,6 +523,12 @@ private:
     TreeViewItem* getNextVisibleItem (bool recurse) const noexcept;
     TreeViewItem* findItemFromIdentifierString (const String& identifierString);
 
+   #if JUCE_CATCH_DEPRECATED_CODE_MISUSE
+    // The parameters for these methods have changed - please update your code!
+    virtual void isInterestedInDragSource (const String&, Component*) {}
+    virtual int itemDropped (const String&, Component*, int) { return 0; }
+   #endif
+
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (TreeViewItem);
 };
 
@@ -769,15 +775,15 @@ public:
     /** @internal */
     void filesDropped (const StringArray& files, int x, int y);
     /** @internal */
-    bool isInterestedInDragSource (const String& sourceDescription, Component* sourceComponent);
+    bool isInterestedInDragSource (const SourceDetails&);
     /** @internal */
-    void itemDragEnter (const String& sourceDescription, Component* sourceComponent, int x, int y);
+    void itemDragEnter (const SourceDetails&);
     /** @internal */
-    void itemDragMove (const String& sourceDescription, Component* sourceComponent, int x, int y);
+    void itemDragMove (const SourceDetails&);
     /** @internal */
-    void itemDragExit (const String& sourceDescription, Component* sourceComponent);
+    void itemDragExit (const SourceDetails&);
     /** @internal */
-    void itemDropped (const String& sourceDescription, Component* sourceComponent, int x, int y);
+    void itemDropped (const SourceDetails&);
 
 private:
     friend class TreeViewItem;
@@ -806,11 +812,10 @@ private:
     void updateButtonUnderMouse (const MouseEvent& e);
     void showDragHighlight (TreeViewItem* item, int insertIndex, int x, int y) noexcept;
     void hideDragHighlight() noexcept;
-    void handleDrag (const StringArray& files, const String& sourceDescription, Component* sourceComponent, int x, int y);
-    void handleDrop (const StringArray& files, const String& sourceDescription, Component* sourceComponent, int x, int y);
+    void handleDrag (const StringArray& files, const SourceDetails&);
+    void handleDrop (const StringArray& files, const SourceDetails&);
     TreeViewItem* getInsertPosition (int& x, int& y, int& insertIndex,
-                                     const StringArray& files, const String& sourceDescription,
-                                     Component* sourceComponent) const noexcept;
+                                     const StringArray& files, const SourceDetails&) const noexcept;
 
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (TreeView);
 };

src/gui/components/layout/juce_MultiDocumentPanel.cpp

@@ -84,7 +84,7 @@ void MultiDocumentPanelWindow::updateOrder()
 MultiDocumentPanel* MultiDocumentPanelWindow::getOwner() const noexcept
 {
     // (unable to use the syntax findParentComponentOfClass <MultiDocumentPanel> () because of a VC6 compiler bug)
-    return findParentComponentOfClass ((MultiDocumentPanel*) 0);
+    return findParentComponentOfClass ((MultiDocumentPanel*) nullptr);
 }
 
 
@@ -104,7 +104,7 @@ public:
     void currentTabChanged (int, const String&)
     {
         // (unable to use the syntax findParentComponentOfClass <MultiDocumentPanel> () because of a VC6 compiler bug)
-        MultiDocumentPanel* const owner = findParentComponentOfClass ((MultiDocumentPanel*) 0);
+        MultiDocumentPanel* const owner = findParentComponentOfClass ((MultiDocumentPanel*) nullptr);
 
         if (owner != nullptr)
             owner->updateOrder();

src/gui/components/menus/juce_PopupMenu.cpp

@@ -1104,7 +1104,7 @@ private:
             PopupMenu::ItemComponent* mic = dynamic_cast <PopupMenu::ItemComponent*> (c);
 
             if (mic == nullptr && c != nullptr)
-                mic = c->findParentComponentOfClass ((PopupMenu::ItemComponent*) 0);
+                mic = c->findParentComponentOfClass ((PopupMenu::ItemComponent*) nullptr);
 
             if (mic != currentChild
                  && (isOver || (activeSubMenu == nullptr) || ! activeSubMenu->isVisible()))

src/gui/components/mouse/juce_DragAndDropContainer.cpp

@@ -51,12 +51,12 @@ public:
                         Component* const sourceComponent,
                         Component* const mouseDragSource_,
                         DragAndDropContainer* const o,
-                        const Point<int>& imageOffset_)
-        : image (im),
-          source (sourceComponent),
+                        const Point<int>& imageOffset_,
+                        ReferenceCountedObject* const customDataObject)
+        : sourceDetails (desc, sourceComponent, Point<int>(), customDataObject),
+          image (im),
           mouseDragSource (mouseDragSource_),
           owner (o),
-          dragDesc (desc),
           imageOffset (imageOffset_),
           hasCheckedForExternalDrag (false),
           drawImage (true)
@@ -64,7 +64,7 @@ public:
         setSize (im.getWidth(), im.getHeight());
 
         if (mouseDragSource == nullptr)
-            mouseDragSource = source;
+            mouseDragSource = sourceComponent;
 
         mouseDragSource->addMouseListener (this, false);
 
@@ -83,8 +83,10 @@ public:
         {
             mouseDragSource->removeMouseListener (this);
 
-            if (getCurrentlyOver() != nullptr && getCurrentlyOver()->isInterestedInDragSource (dragDesc, source))
-                getCurrentlyOver()->itemDragExit (dragDesc, source);
+            DragAndDropTarget* const current = getCurrentlyOver();
+
+            if (current != nullptr && current->isInterestedInDragSource (sourceDetails))
+                current->itemDragExit (sourceDetails);
         }
     }
 
@@ -114,15 +116,15 @@ public:
             hit = hit->getComponentAt (relPos.getX(), relPos.getY());
         }
 
-        // (note: use a local copy of the dragDesc member in case the callback runs
+        // (note: use a local copy of this in case the callback runs
         // a modal loop and deletes this object before the method completes)
-        const String dragDescLocal (dragDesc);
+        const DragAndDropTarget::SourceDetails details (sourceDetails);
 
         while (hit != nullptr)
         {
             DragAndDropTarget* const ddt = dynamic_cast <DragAndDropTarget*> (hit);
 
-            if (ddt != nullptr && ddt->isInterestedInDragSource (dragDescLocal, source))
+            if (ddt != nullptr && ddt->isInterestedInDragSource (details))
             {
                 relativePos = hit->getLocalPoint (nullptr, screenPos);
                 return ddt;
@@ -156,13 +158,13 @@ public:
 
                 setVisible (true);
 
-                if (dropAccepted || source == nullptr)
+                if (dropAccepted || sourceDetails.sourceComponent == nullptr)
                 {
                     Desktop::getInstance().getAnimator().fadeOut (this, 120);
                 }
                 else
                 {
-                    const Point<int> target (source->localPointToGlobal (source->getLocalBounds().getCentre()));
+                    const Point<int> target (sourceDetails.sourceComponent->localPointToGlobal (sourceDetails.sourceComponent->getLocalBounds().getCentre()));
                     const Point<int> ourCentre (localPointToGlobal (getLocalBounds().getCentre()));
 
                     Desktop::getInstance().getAnimator().animateComponent (this,
@@ -177,13 +179,14 @@ public:
 
             if (dropAccepted && ddt != nullptr)
             {
-                // (note: use a local copy of the dragDesc member in case the callback runs
+                // (note: use a local copy of this in case the callback runs
                 // a modal loop and deletes this object before the method completes)
-                const String dragDescLocal (dragDesc);
+                DragAndDropTarget::SourceDetails details (sourceDetails);
+                details.localPosition = relPos;
 
                 currentlyOverComp = nullptr;
 
-                ddt->itemDropped (dragDescLocal, source, relPos.getX(), relPos.getY());
+                ddt->itemDropped (details);
             }
 
             // careful - this object could now be deleted..
@@ -192,9 +195,9 @@ public:
 
     void updateLocation (const bool canDoExternalDrag, const Point<int>& screenPos)
     {
-        // (note: use a local copy of the dragDesc member in case the callback runs
-        // a modal loop and deletes this object before it returns)
-        const String dragDescLocal (dragDesc);
+        // (note: use a local copy of this in case a callback runs a modal loop and deletes
+        // this object before it returns)
+        DragAndDropTarget::SourceDetails details (sourceDetails);
 
         Point<int> newPos (screenPos + imageOffset);
 
@@ -206,29 +209,41 @@ public:
             setTopLeftPosition (newPos.getX(), newPos.getY());
 
             Point<int> relPos;
-            DragAndDropTarget* const ddt = findTarget (screenPos, relPos);
-            Component* ddtComp = dynamic_cast <Component*> (ddt);
+            DragAndDropTarget* const newTarget = findTarget (screenPos, relPos);
+            Component* newTargetComp = dynamic_cast <Component*> (newTarget);
 
-            drawImage = (ddt == nullptr) || ddt->shouldDrawDragImageWhenOver();
+            drawImage = (newTarget == nullptr) || newTarget->shouldDrawDragImageWhenOver();
 
-            if (ddtComp != currentlyOverComp)
+            if (newTargetComp != currentlyOverComp)
             {
-                if (currentlyOverComp != nullptr && source != nullptr
-                      && getCurrentlyOver()->isInterestedInDragSource (dragDescLocal, source))
+                DragAndDropTarget* const lastTarget = getCurrentlyOver();
+
+                if (lastTarget != nullptr && details.sourceComponent != nullptr
+                      && lastTarget->isInterestedInDragSource (details))
+                    lastTarget->itemDragExit (details);
+
+                currentlyOverComp = newTargetComp;
+
+                if (newTarget != nullptr)
                 {
-                    getCurrentlyOver()->itemDragExit (dragDescLocal, source);
+                    details.localPosition = relPos;
+
+                    if (newTarget->isInterestedInDragSource (details))
+                        newTarget->itemDragEnter (details);
                 }
+            }
 
-                currentlyOverComp = ddtComp;
+            {
+                DragAndDropTarget* const target = getCurrentlyOver();
+                if (target != nullptr)
+                {
+                    details.localPosition = relPos;
 
-                if (ddt != nullptr && ddt->isInterestedInDragSource (dragDescLocal, source))
-                    ddt->itemDragEnter (dragDescLocal, source, relPos.getX(), relPos.getY());
+                    if (target->isInterestedInDragSource (details))
+                        target->itemDragMove (details);
+                }
             }
 
-            DragAndDropTarget* target = getCurrentlyOver();
-            if (target != nullptr && target->isInterestedInDragSource (dragDescLocal, source))
-                target->itemDragMove (dragDescLocal, source, relPos.getX(), relPos.getY());
-
             if (getCurrentlyOver() == nullptr && canDoExternalDrag && ! hasCheckedForExternalDrag)
             {
                 if (Desktop::getInstance().findComponentAt (screenPos) == nullptr)
@@ -237,7 +252,7 @@ public:
                     StringArray files;
                     bool canMoveFiles = false;
 
-                    if (owner->shouldDropFilesWhenDraggedExternally (dragDescLocal, source, files, canMoveFiles)
+                    if (owner->shouldDropFilesWhenDraggedExternally (details, files, canMoveFiles)
                          && files.size() > 0)
                     {
                         WeakReference<Component> thisWeakRef (this);
@@ -262,7 +277,7 @@ public:
 
     void timerCallback()
     {
-        if (source == nullptr)
+        if (sourceDetails.sourceComponent == nullptr)
         {
             delete this;
         }
@@ -276,8 +291,8 @@ public:
     }
 
 private:
+    DragAndDropTarget::SourceDetails sourceDetails;
     Image image;
-    WeakReference<Component> source;
     WeakReference<Component> mouseDragSource;
     DragAndDropContainer* const owner;
 
@@ -287,7 +302,6 @@ private:
         return dynamic_cast <DragAndDropTarget*> (currentlyOverComp.get());
     }
 
-    String dragDesc;
     const Point<int> imageOffset;
     bool hasCheckedForExternalDrag, drawImage;
 
@@ -309,7 +323,8 @@ void DragAndDropContainer::startDragging (const String& sourceDescription,
                                           Component* sourceComponent,
                                           const Image& dragImage_,
                                           const bool allowDraggingToExternalWindows,
-                                          const Point<int>* imageOffsetFromMouse)
+                                          const Point<int>* imageOffsetFromMouse,
+                                          ReferenceCountedObject* customDataObject)
 {
     Image dragImage (dragImage_);
 
@@ -378,7 +393,8 @@ void DragAndDropContainer::startDragging (const String& sourceDescription,
         }
 
         dragImageComponent = new DragImageComponent (dragImage, sourceDescription, sourceComponent,
-                                                     draggingSource->getComponentUnderMouse(), this, imageOffset);
+                                                     draggingSource->getComponentUnderMouse(), this,
+                                                     imageOffset, customDataObject);
 
         currentDragDesc = sourceDescription;
 
@@ -420,46 +436,33 @@ const String DragAndDropContainer::getCurrentDragDescription() const
 
 DragAndDropContainer* DragAndDropContainer::findParentDragContainerFor (Component* c)
 {
-    return c == nullptr ? nullptr : c->findParentComponentOfClass ((DragAndDropContainer*) 0);
+    return c == nullptr ? nullptr : c->findParentComponentOfClass ((DragAndDropContainer*) nullptr);
 }
 
-bool DragAndDropContainer::shouldDropFilesWhenDraggedExternally (const String&, Component*, StringArray&, bool&)
+bool DragAndDropContainer::shouldDropFilesWhenDraggedExternally (const DragAndDropTarget::SourceDetails&, StringArray&, bool&)
 {
     return false;
 }
 
-
 //==============================================================================
-void DragAndDropTarget::itemDragEnter (const String&, Component*, int, int)
-{
-}
-
-void DragAndDropTarget::itemDragMove (const String&, Component*, int, int)
+DragAndDropTarget::SourceDetails::SourceDetails (const String& description_, Component* sourceComponent_,
+                                                 const Point<int>& localPosition_, ReferenceCountedObject* const customDataObject_) noexcept
+    : description (description_),
+      sourceComponent (sourceComponent_),
+      localPosition (localPosition_),
+      customDataObject (customDataObject_)
 {
 }
 
-void DragAndDropTarget::itemDragExit (const String&, Component*)
-{
-}
-
-bool DragAndDropTarget::shouldDrawDragImageWhenOver()
-{
-    return true;
-}
-
+void DragAndDropTarget::itemDragEnter (const SourceDetails&)  {}
+void DragAndDropTarget::itemDragMove  (const SourceDetails&)  {}
+void DragAndDropTarget::itemDragExit  (const SourceDetails&)  {}
+bool DragAndDropTarget::shouldDrawDragImageWhenOver()         { return true; }
 
 //==============================================================================
-void FileDragAndDropTarget::fileDragEnter (const StringArray&, int, int)
-{
-}
-
-void FileDragAndDropTarget::fileDragMove (const StringArray&, int, int)
-{
-}
-
-void FileDragAndDropTarget::fileDragExit (const StringArray&)
-{
-}
+void FileDragAndDropTarget::fileDragEnter (const StringArray&, int, int)  {}
+void FileDragAndDropTarget::fileDragMove  (const StringArray&, int, int)  {}
+void FileDragAndDropTarget::fileDragExit  (const StringArray&)            {}
 
 
 END_JUCE_NAMESPACE

src/gui/components/mouse/juce_DragAndDropContainer.h

@@ -73,10 +73,9 @@ public:
         findParentDragContainerFor() is a handy method to call to find the
         drag container to use for a component.
 
-        @param sourceDescription    a string to use as the description of the thing being
-                                    dragged - this will be passed to the objects that might be
-                                    dropped-onto so they can decide if they want to handle it or
-                                    not
+        @param sourceDescription    a string to use as the description of the thing being dragged - this
+                                    will be passed to the objects that might be dropped-onto so they can
+                                    decide whether they want to handle it
         @param sourceComponent      the component that is being dragged
         @param dragImage            the image to drag around underneath the mouse. If this is a null image,
                                     a snapshot of the sourceComponent will be used instead.
@@ -87,12 +86,16 @@ public:
                                     at which the image should be drawn from the mouse. If it isn't
                                     specified, then the image will be centred around the mouse. If
                                     an image hasn't been passed-in, this will be ignored.
+        @param customDataObject     Any kind of reference-counted object which you want to have passed to
+                                    the target component. A pointer to this object will be made available
+                                    to the targets in the DragAndDropTarget::SourceDetails class.
     */
     void startDragging (const String& sourceDescription,
                         Component* sourceComponent,
                         const Image& dragImage = Image::null,
                         bool allowDraggingToOtherJuceWindows = false,
-                        const Point<int>* imageOffsetFromMouse = nullptr);
+                        const Point<int>* imageOffsetFromMouse = nullptr,
+                        ReferenceCountedObject* customDataObject = nullptr);
 
     /** Returns true if something is currently being dragged. */
     bool isDragAndDropActive() const;
@@ -168,8 +171,7 @@ protected:
                                             method)
         @see performExternalDragDropOfFiles
     */
-    virtual bool shouldDropFilesWhenDraggedExternally (const String& dragSourceDescription,
-                                                       Component* dragSourceComponent,
+    virtual bool shouldDropFilesWhenDraggedExternally (const DragAndDropTarget::SourceDetails& sourceDetails,
                                                        StringArray& files,
                                                        bool& canMoveFiles);
 
@@ -179,6 +181,8 @@ private:
     ScopedPointer <Component> dragImageComponent;
     String currentDragDesc;
 
+    JUCE_DEPRECATED (virtual bool shouldDropFilesWhenDraggedExternally (const String&, Component*, StringArray&, bool&)) { return false; }
+
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (DragAndDropContainer);
 };
 

src/gui/components/mouse/juce_DragAndDropTarget.h

@@ -49,16 +49,44 @@ public:
     /** Destructor. */
     virtual ~DragAndDropTarget()  {}
 
+    //==============================================================================
+    /** Contains details about the source of a drag-and-drop operation.
+        The contents of this
+    */
+    class JUCE_API  SourceDetails
+    {
+    public:
+        /** Creates a SourceDetails object from its various settings. */
+        SourceDetails (const String& description, Component* sourceComponent,
+                       const Point<int>& localPosition, ReferenceCountedObject* customDataObject = nullptr) noexcept;
+
+        /** A descriptor string - this is set DragAndDropContainer::startDragging(). */
+        String description;
+
+        /** The component from the drag operation was started. */
+        WeakReference<Component> sourceComponent;
+
+        /** The local position of the mouse, relative to the target component.
+            Note that for calls such as isInterestedInDragSource(), this may be a null position.
+        */
+        Point<int> localPosition;
+
+        /** A pointer to a user-supplied object which contains some kind of data which is relevant to
+            the specific classes which are being used. Make sure that you check the type of this object,
+            and safely dynamic_cast it to your required type.
+        */
+        ReferenceCountedObjectPtr<ReferenceCountedObject> customDataObject;
+    };
+
+    //==============================================================================
     /** Callback to check whether this target is interested in the type of object being
         dragged.
 
-        @param sourceDescription    the description string passed into DragAndDropContainer::startDragging()
-        @param sourceComponent      the component that was passed into DragAndDropContainer::startDragging()
+        @param dragSourceDetails    contains information about the source of the drag operation.
         @returns                    true if this component wants to receive the other callbacks regarging this
                                     type of object; if it returns false, no other callbacks will be made.
     */
-    virtual bool isInterestedInDragSource (const String& sourceDescription,
-                                           Component* sourceComponent) = 0;
+    virtual bool isInterestedInDragSource (const SourceDetails& dragSourceDetails) = 0;
 
     /** Callback to indicate that something is being dragged over this component.
 
@@ -68,15 +96,10 @@ public:
         Use this callback as a trigger to make your component repaint itself to give the
         user feedback about whether the item can be dropped here or not.
 
-        @param sourceDescription    the description string passed into DragAndDropContainer::startDragging()
-        @param sourceComponent      the component that was passed into DragAndDropContainer::startDragging()
-        @param x                    the mouse x position, relative to this component
-        @param y                    the mouse y position, relative to this component
+        @param dragSourceDetails    contains information about the source of the drag operation.
         @see itemDragExit
     */
-    virtual void itemDragEnter (const String& sourceDescription,
-                                Component* sourceComponent,
-                                int x, int y);
+    virtual void itemDragEnter (const SourceDetails& dragSourceDetails);
 
     /** Callback to indicate that the user is dragging something over this component.
 
@@ -84,14 +107,9 @@ public:
         something. Normally overriding itemDragEnter() and itemDragExit() are enough, but
         this lets you know what happens in-between.
 
-        @param sourceDescription    the description string passed into DragAndDropContainer::startDragging()
-        @param sourceComponent      the component that was passed into DragAndDropContainer::startDragging()
-        @param x                    the mouse x position, relative to this component
-        @param y                    the mouse y position, relative to this component
+        @param dragSourceDetails    contains information about the source of the drag operation.
     */
-    virtual void itemDragMove (const String& sourceDescription,
-                               Component* sourceComponent,
-                               int x, int y);
+    virtual void itemDragMove (const SourceDetails& dragSourceDetails);
 
     /** Callback to indicate that something has been dragged off the edge of this component.
 
@@ -101,12 +119,10 @@ public:
         If you've used itemDragEnter() to repaint your component and give feedback, use this
         as a signal to repaint it in its normal state.
 
-        @param sourceDescription    the description string passed into DragAndDropContainer::startDragging()
-        @param sourceComponent      the component that was passed into DragAndDropContainer::startDragging()
+        @param dragSourceDetails    contains information about the source of the drag operation.
         @see itemDragEnter
     */
-    virtual void itemDragExit (const String& sourceDescription,
-                               Component* sourceComponent);
+    virtual void itemDragExit (const SourceDetails& dragSourceDetails);
 
     /** Callback to indicate that the user has dropped something onto this component.
 
@@ -116,14 +132,9 @@ public:
         Note that after this is called, the itemDragExit method may not be called, so you should
         clean up in here if there's anything you need to do when the drag finishes.
 
-        @param sourceDescription    the description string passed into DragAndDropContainer::startDragging()
-        @param sourceComponent      the component that was passed into DragAndDropContainer::startDragging()
-        @param x                    the mouse x position, relative to this component
-        @param y                    the mouse y position, relative to this component
+        @param dragSourceDetails    contains information about the source of the drag operation.
     */
-    virtual void itemDropped (const String& sourceDescription,
-                              Component* sourceComponent,
-                              int x, int y) = 0;
+    virtual void itemDropped (const SourceDetails& dragSourceDetails) = 0;
 
     /** Overriding this allows the target to tell the drag container whether to
         draw the drag image while the cursor is over it.
@@ -132,7 +143,18 @@ public:
         image will not be shown when the cursor is over this target.
     */
     virtual bool shouldDrawDragImageWhenOver();
-};
 
 
+    //==============================================================================
+private:
+   #if JUCE_CATCH_DEPRECATED_CODE_MISUSE
+    // The parameters for these methods have changed - please update your code!
+    virtual void isInterestedInDragSource (const String&, Component*) {}
+    virtual int itemDragEnter (const String&, Component*, int, int) { return 0; }
+    virtual int itemDragMove (const String&, Component*, int, int) { return 0; }
+    virtual int itemDragExit (const String&, Component*) { return 0; }
+    virtual int itemDropped (const String&, Component*, int, int) { return 0; }
+   #endif
+};
+
 #endif   // __JUCE_DRAGANDDROPTARGET_JUCEHEADER__

src/gui/components/properties/juce_PropertyPanel.cpp

@@ -97,7 +97,7 @@ public:
             for (int i = propertyComps.size(); --i >= 0;)
                 propertyComps.getUnchecked(i)->setVisible (open);
 
-            PropertyPanel* const pp = findParentComponentOfClass ((PropertyPanel*) 0);
+            PropertyPanel* const pp = findParentComponentOfClass ((PropertyPanel*) nullptr);
 
             if (pp != nullptr)
                 pp->resized();

src/gui/components/windows/juce_DialogWindow.h

@@ -87,7 +87,7 @@ public:
         the DialogWindow that is created. To find a pointer to this window from your
         contentComponent, you can do something like this:
         @code
-        Dialogwindow* dw = contentComponent->findParentComponentOfClass ((DialogWindow*) 0);
+        Dialogwindow* dw = contentComponent->findParentComponentOfClass ((DialogWindow*) nullptr);
 
         if (dw != nullptr)
             dw->exitModalState (1234);
@@ -130,7 +130,7 @@ public:
         the DialogWindow that is created. To find a pointer to this window from your
         contentComponent, you can do something like this:
         @code
-        Dialogwindow* dw = contentComponent->findParentComponentOfClass ((DialogWindow*) 0);
+        Dialogwindow* dw = contentComponent->findParentComponentOfClass ((DialogWindow*) nullptr);
 
         if (dw != nullptr)
             dw->exitModalState (1234);

src/gui/components/windows/juce_TooltipWindow.cpp

@@ -85,22 +85,35 @@ void TooltipWindow::showFor (const String& tip)
     tipShowing = tip;
 
     Point<int> mousePos (Desktop::getMousePosition());
+    Rectangle<int> parentArea;
 
     if (getParentComponent() != nullptr)
+    {
         mousePos = getParentComponent()->getLocalPoint (nullptr, mousePos);
+        parentArea = getParentComponent()->getLocalBounds();
+    }
+    else
+    {
+        parentArea = Desktop::getInstance().getMonitorAreaContaining (mousePos);
+    }
 
-    int x, y, w, h;
+    int w, h;
     getLookAndFeel().getTooltipSize (tip, w, h);
 
-    if (mousePos.getX() > getParentWidth() / 2)
-        x = mousePos.getX() - (w + 12);
+    int x = mousePos.getX();
+    if (x > parentArea.getCentreX())
+        x -= (w + 12);
     else
-        x = mousePos.getX() + 24;
+        x += 24;
 
-    if (mousePos.getY() > getParentHeight() / 2)
-        y = mousePos.getY() - (h + 6);
+    int y = mousePos.getY();
+    if (y > parentArea.getCentreY())
+        y -= (h + 6);
     else
-        y = mousePos.getY() + 6;
+        y += 6;
+
+    x = jlimit (parentArea.getX(), parentArea.getRight() - w, x);
+    y = jlimit (parentArea.getY(), parentArea.getBottom() - h, y);
 
     setBounds (x, y, w, h);
     setVisible (true);

src/gui/components/windows/juce_TopLevelWindow.cpp

@@ -71,7 +71,7 @@ public:
 
             if (tlw == nullptr && c != nullptr)
                 // (unable to use the syntax findParentComponentOfClass <TopLevelWindow> () because of a VC6 compiler bug)
-                tlw = c->findParentComponentOfClass ((TopLevelWindow*) 0);
+                tlw = c->findParentComponentOfClass ((TopLevelWindow*) nullptr);
 
             if (tlw != nullptr)
                 active = tlw;