diff --git a/include/event.hpp b/include/event.hpp
index 4e314c18..7a0e33bb 100644
--- a/include/event.hpp
+++ b/include/event.hpp
@@ -346,10 +346,10 @@ struct Change : Base {
 };
 
 
-/** Occurs after the zoom level of a Widget is changed.
+/** Occurs when the pixel buffer of this module must be refreshed.
 Recurses.
 */
-struct Zoom : Base {
+struct Dirty : Base {
 };
 
 
@@ -436,7 +436,7 @@ struct State {
 	bool handleText(math::Vec pos, int codepoint);
 	bool handleKey(math::Vec pos, int key, int scancode, int action, int mods);
 	bool handleDrop(math::Vec pos, const std::vector<std::string>& paths);
-	bool handleZoom();
+	bool handleDirty();
 };
 
 
diff --git a/include/widget/FramebufferWidget.hpp b/include/widget/FramebufferWidget.hpp
index e83ec25b..d8419c35 100644
--- a/include/widget/FramebufferWidget.hpp
+++ b/include/widget/FramebufferWidget.hpp
@@ -33,6 +33,7 @@ struct FramebufferWidget : Widget {
 
 	FramebufferWidget();
 	~FramebufferWidget();
+	void onDirty(const event::Dirty& e) override;
 	void step() override;
 	void draw(const DrawArgs& args) override;
 	virtual void drawFramebuffer();
diff --git a/include/widget/Widget.hpp b/include/widget/Widget.hpp
index 4d63730b..448df63f 100644
--- a/include/widget/Widget.hpp
+++ b/include/widget/Widget.hpp
@@ -34,9 +34,18 @@ struct Widget {
 	virtual ~Widget();
 
 	void setPosition(math::Vec pos);
+	math::Vec getPosition() {
+		return box.pos;
+	}
 	void setSize(math::Vec size);
+	math::Vec getSize() {
+		return box.size;
+	}
 	void show();
 	void hide();
+	bool isVisible() {
+		return visible;
+	}
 	void requestDelete();
 
 	virtual math::Rect getChildrenBoundingBox();
@@ -180,8 +189,8 @@ struct Widget {
 	}
 	virtual void onAction(const event::Action& e) {}
 	virtual void onChange(const event::Change& e) {}
-	virtual void onZoom(const event::Zoom& e) {
-		recurseEvent(&Widget::onZoom, e);
+	virtual void onDirty(const event::Dirty& e) {
+		recurseEvent(&Widget::onDirty, e);
 	}
 	virtual void onReposition(const event::Reposition& e) {}
 	virtual void onResize(const event::Resize& e) {}
diff --git a/include/widget/ZoomWidget.hpp b/include/widget/ZoomWidget.hpp
index 10003720..ee3f5cfc 100644
--- a/include/widget/ZoomWidget.hpp
+++ b/include/widget/ZoomWidget.hpp
@@ -13,6 +13,9 @@ struct ZoomWidget : Widget {
 	math::Vec getRelativeOffset(math::Vec v, Widget* relative) override;
 	math::Rect getViewport(math::Rect r) override;
 	void setZoom(float zoom);
+	float getZoom() {
+		return zoom;
+	}
 	void draw(const DrawArgs& args) override;
 
 	void onHover(const event::Hover& e) override {
diff --git a/src/app/RackWidget.cpp b/src/app/RackWidget.cpp
index a227a6ab..07d7729e 100644
--- a/src/app/RackWidget.cpp
+++ b/src/app/RackWidget.cpp
@@ -402,13 +402,12 @@ bool RackWidget::requestModulePos(ModuleWidget* mw, math::Vec pos) {
 		if (!w2->visible)
 			continue;
 		// Check intersection
-		if (mwBox.isIntersecting(w2->box)) {
+		if (mwBox.isIntersecting(w2->box))
 			return false;
-		}
 	}
 
 	// Accept requested position
-	mw->box = mwBox;
+	mw->setPosition(mwBox.pos);
 	RackWidget_updateAdjacent(this);
 	return true;
 }
@@ -459,11 +458,11 @@ void RackWidget::setModulePosNearest(ModuleWidget* mw, math::Vec pos) {
 	}
 
 	// We failed to find a box. This shouldn't happen on an infinite rack.
-	assert(0);
+	assert(false);
 }
 
 void RackWidget::setModulePosForce(ModuleWidget* mw, math::Vec pos) {
-	mw->box.pos = pos.div(RACK_GRID_SIZE).round().mult(RACK_GRID_SIZE);
+	mw->setPosition(pos.div(RACK_GRID_SIZE).round().mult(RACK_GRID_SIZE));
 
 	// Comparison of center X coordinates
 	auto cmp = [&](const widget::Widget * a, const widget::Widget * b) {
@@ -489,24 +488,26 @@ void RackWidget::setModulePosForce(ModuleWidget* mw, math::Vec pos) {
 	float xLimit = mw->box.pos.x;
 	for (auto it = leftModules.rbegin(); it != leftModules.rend(); it++) {
 		widget::Widget* w = *it;
-		float x = xLimit - w->box.size.x;
-		x = std::round(x / RACK_GRID_WIDTH) * RACK_GRID_WIDTH;
-		if (w->box.pos.x < x)
+		math::Vec newPos = w->box.pos;
+		newPos.x = xLimit - w->box.size.x;
+		newPos.x = std::round(newPos.x / RACK_GRID_WIDTH) * RACK_GRID_WIDTH;
+		if (w->box.pos.x < newPos.x)
 			break;
-		w->box.pos.x = x;
-		xLimit = x;
+		w->setPosition(newPos);
+		xLimit = newPos.x;
 	}
 
 	// Shove right modules
 	xLimit = mw->box.pos.x + mw->box.size.x;
 	for (auto it = rightModules.begin(); it != rightModules.end(); it++) {
 		widget::Widget* w = *it;
-		float x = xLimit;
-		x = std::round(x / RACK_GRID_WIDTH) * RACK_GRID_WIDTH;
-		if (w->box.pos.x > x)
+		math::Vec newPos = w->box.pos;
+		newPos.x = xLimit;
+		newPos.x = std::round(newPos.x / RACK_GRID_WIDTH) * RACK_GRID_WIDTH;
+		if (w->box.pos.x > newPos.x)
 			break;
-		w->box.pos.x = x;
-		xLimit = x + w->box.size.x;
+		w->setPosition(newPos);
+		xLimit = newPos.x + w->box.size.x;
 	}
 
 	RackWidget_updateAdjacent(this);
diff --git a/src/event.cpp b/src/event.cpp
index 7471ba79..b6beb07f 100644
--- a/src/event.cpp
+++ b/src/event.cpp
@@ -13,14 +13,14 @@ void State::setHovered(widget::Widget* w) {
 		return;
 
 	if (hoveredWidget) {
-		// Leave
+		// Trigger Leave event
 		Leave eLeave;
 		hoveredWidget->onLeave(eLeave);
 		hoveredWidget = NULL;
 	}
 
 	if (w) {
-		// Enter
+		// Trigger Enter event
 		Context cEnter;
 		cEnter.target = w;
 		Enter eEnter;
@@ -35,7 +35,7 @@ void State::setDragged(widget::Widget* w, int button) {
 		return;
 
 	if (draggedWidget) {
-		// DragEnd
+		// Trigger DragEnd event
 		DragEnd eDragEnd;
 		eDragEnd.button = dragButton;
 		draggedWidget->onDragEnd(eDragEnd);
@@ -45,7 +45,7 @@ void State::setDragged(widget::Widget* w, int button) {
 	dragButton = button;
 
 	if (w) {
-		// DragStart
+		// Trigger DragStart event
 		Context cDragStart;
 		cDragStart.target = w;
 		DragStart eDragStart;
@@ -61,7 +61,7 @@ void State::setDragHovered(widget::Widget* w) {
 		return;
 
 	if (dragHoveredWidget) {
-		// DragLeave
+		// Trigger DragLeave event
 		DragLeave eDragLeave;
 		eDragLeave.button = dragButton;
 		eDragLeave.origin = draggedWidget;
@@ -70,7 +70,7 @@ void State::setDragHovered(widget::Widget* w) {
 	}
 
 	if (w) {
-		// DragEnter
+		// Trigger DragEnter event
 		Context cDragEnter;
 		cDragEnter.target = w;
 		DragEnter eDragEnter;
@@ -87,14 +87,14 @@ void State::setSelected(widget::Widget* w) {
 		return;
 
 	if (selectedWidget) {
-		// Deselect
+		// Trigger Deselect event
 		Deselect eDeselect;
 		selectedWidget->onDeselect(eDeselect);
 		selectedWidget = NULL;
 	}
 
 	if (w) {
-		// Select
+		// Trigger Select event
 		Context cSelect;
 		cSelect.target = w;
 		Select eSelect;
@@ -122,7 +122,7 @@ bool State::handleButton(math::Vec pos, int button, int action, int mods) {
 
 	widget::Widget* clickedWidget = NULL;
 	if (!cursorLocked) {
-		// Button
+		// Trigger Button event
 		Context cButton;
 		Button eButton;
 		eButton.context = &cButton;
@@ -142,7 +142,7 @@ bool State::handleButton(math::Vec pos, int button, int action, int mods) {
 		setDragHovered(NULL);
 
 		if (clickedWidget && draggedWidget) {
-			// DragDrop
+			// Trigger DragDrop event
 			DragDrop eDragDrop;
 			eDragDrop.button = dragButton;
 			eDragDrop.origin = draggedWidget;
@@ -163,7 +163,7 @@ bool State::handleButton(math::Vec pos, int button, int action, int mods) {
 			if (clickedWidget
 			    && clickTime - lastClickTime <= doubleClickDuration
 			    && lastClickedWidget == clickedWidget) {
-				// DoubleClick
+				// Trigger DoubleClick event
 				DoubleClick eDoubleClick;
 				clickedWidget->onDoubleClick(eDoubleClick);
 				// Reset double click
@@ -193,14 +193,14 @@ bool State::handleHover(math::Vec pos, math::Vec mouseDelta) {
 	}
 
 	if (draggedWidget) {
-		// DragMove
+		// Trigger DragMove event
 		DragMove eDragMove;
 		eDragMove.button = dragButton;
 		eDragMove.mouseDelta = mouseDelta;
 		draggedWidget->onDragMove(eDragMove);
 
 		if (!cursorLocked) {
-			// DragHover
+			// Trigger DragHover event
 			Context cDragHover;
 			DragHover eDragHover;
 			eDragHover.context = &cDragHover;
@@ -217,7 +217,7 @@ bool State::handleHover(math::Vec pos, math::Vec mouseDelta) {
 	}
 
 	if (!cursorLocked) {
-		// Hover
+		// Trigger Hover event
 		Context cHover;
 		Hover eHover;
 		eHover.context = &cHover;
@@ -240,7 +240,7 @@ bool State::handleLeave() {
 }
 
 bool State::handleScroll(math::Vec pos, math::Vec scrollDelta) {
-	// HoverScroll
+	// Trigger HoverScroll event
 	Context cHoverScroll;
 	HoverScroll eHoverScroll;
 	eHoverScroll.context = &cHoverScroll;
@@ -252,7 +252,7 @@ bool State::handleScroll(math::Vec pos, math::Vec scrollDelta) {
 }
 
 bool State::handleDrop(math::Vec pos, const std::vector<std::string>& paths) {
-	// PathDrop
+	// Trigger PathDrop event
 	Context cPathDrop;
 	PathDrop ePathDrop(paths);
 	ePathDrop.context = &cPathDrop;
@@ -264,7 +264,7 @@ bool State::handleDrop(math::Vec pos, const std::vector<std::string>& paths) {
 
 bool State::handleText(math::Vec pos, int codepoint) {
 	if (selectedWidget) {
-		// SelectText
+		// Trigger SelectText event
 		Context cSelectText;
 		SelectText eSelectText;
 		eSelectText.context = &cSelectText;
@@ -274,7 +274,7 @@ bool State::handleText(math::Vec pos, int codepoint) {
 			return true;
 	}
 
-	// HoverText
+	// Trigger HoverText event
 	Context cHoverText;
 	HoverText eHoverText;
 	eHoverText.context = &cHoverText;
@@ -297,7 +297,7 @@ bool State::handleKey(math::Vec pos, int key, int scancode, int action, int mods
 	}
 
 	if (selectedWidget) {
-		// SelectKey
+		// Trigger SelectKey event
 		Context cSelectKey;
 		SelectKey eSelectKey;
 		eSelectKey.context = &cSelectKey;
@@ -313,7 +313,7 @@ bool State::handleKey(math::Vec pos, int key, int scancode, int action, int mods
 			return true;
 	}
 
-	// HoverKey
+	// Trigger HoverKey event
 	Context cHoverKey;
 	HoverKey eHoverKey;
 	eHoverKey.context = &cHoverKey;
@@ -329,12 +329,12 @@ bool State::handleKey(math::Vec pos, int key, int scancode, int action, int mods
 	return !!cHoverKey.target;
 }
 
-bool State::handleZoom() {
-	// Zoom
-	Context cZoom;
-	Zoom eZoom;
-	eZoom.context = &cZoom;
-	rootWidget->onZoom(eZoom);
+bool State::handleDirty() {
+	// Trigger Dirty event
+	Context cDirty;
+	Dirty eDirty;
+	eDirty.context = &cDirty;
+	rootWidget->onDirty(eDirty);
 	return true;
 }
 
diff --git a/src/widget/FramebufferWidget.cpp b/src/widget/FramebufferWidget.cpp
index c9a34de7..f50539b7 100644
--- a/src/widget/FramebufferWidget.cpp
+++ b/src/widget/FramebufferWidget.cpp
@@ -15,6 +15,11 @@ FramebufferWidget::~FramebufferWidget() {
 		nvgluDeleteFramebuffer(fb);
 }
 
+void FramebufferWidget::onDirty(const event::Dirty& e) {
+	dirty = true;
+	Widget::onDirty(e);
+}
+
 void FramebufferWidget::step() {
 	Widget::step();
 
diff --git a/src/widget/Widget.cpp b/src/widget/Widget.cpp
index dfc94d02..fd8dec96 100644
--- a/src/widget/Widget.cpp
+++ b/src/widget/Widget.cpp
@@ -15,6 +15,8 @@ Widget::~Widget() {
 }
 
 void Widget::setPosition(math::Vec pos) {
+	if (pos.isEqual(box.pos))
+		return;
 	box.pos = pos;
 	// event::Reposition
 	event::Reposition eReposition;
@@ -22,6 +24,8 @@ void Widget::setPosition(math::Vec pos) {
 }
 
 void Widget::setSize(math::Vec size) {
+	if (size.isEqual(box.size))
+		return;
 	box.size = size;
 	// event::Resize
 	event::Resize eResize;
diff --git a/src/widget/ZoomWidget.cpp b/src/widget/ZoomWidget.cpp
index 4543c160..c4ffca85 100644
--- a/src/widget/ZoomWidget.cpp
+++ b/src/widget/ZoomWidget.cpp
@@ -23,10 +23,11 @@ void ZoomWidget::setZoom(float zoom) {
 		return;
 	this->zoom = zoom;
 
-	event::Context cZoom;
-	event::Zoom eZoom;
-	eZoom.context = &cZoom;
-	Widget::onZoom(eZoom);
+	// Trigger Dirty event
+	event::Context cDirty;
+	event::Dirty eDirty;
+	eDirty.context = &cDirty;
+	Widget::onDirty(eDirty);
 }
 
 void ZoomWidget::draw(const DrawArgs& args) {
diff --git a/src/window.cpp b/src/window.cpp
index 789c9614..a04fbcc9 100644
--- a/src/window.cpp
+++ b/src/window.cpp
@@ -384,7 +384,7 @@ void Window::run() {
 		glfwGetWindowContentScale(win, &newPixelRatio, NULL);
 		newPixelRatio = std::floor(newPixelRatio + 0.5);
 		if (newPixelRatio != pixelRatio) {
-			APP->event->handleZoom();
+			APP->event->handleDirty();
 			pixelRatio = newPixelRatio;
 		}