diff --git a/juce_amalgamated.cpp b/juce_amalgamated.cpp
index de5535bfc5..71a77bfd2b 100644
--- a/juce_amalgamated.cpp
+++ b/juce_amalgamated.cpp
@@ -244136,7 +244136,7 @@ namespace FileChooserHelpers
 			if (ofn->hdr.code == CDN_SELCHANGE)
 			{
 				FileChooserCallbackInfo* info = (FileChooserCallbackInfo*) ofn->lpOFN->lCustData;
-				FilePreviewComponent* comp = static_cast<FilePreviewComponent*> (info->customComponent->getChildComponent(0));
+				FilePreviewComponent* comp = dynamic_cast<FilePreviewComponent*> (info->customComponent->getChildComponent(0));
 
 				if (comp != 0)
 				{
@@ -244170,8 +244170,9 @@ namespace FileChooserHelpers
 
 		void resized()
 		{
-			if (getNumChildComponents() > 0)
-				getChildComponent(0)->setBounds (getLocalBounds());
+			Component* const c = getChildComponent(0);
+			if (c != 0)
+				c->setBounds (getLocalBounds());
 		}
 
 	private:
@@ -244179,13 +244180,14 @@ namespace FileChooserHelpers
 	};
 }
 
-void FileChooser::showPlatformDialog (Array<File>& results, const String& title, const File& currentFileOrDirectory,
+void FileChooser::showPlatformDialog (Array<File>& results, const String& title_, const File& currentFileOrDirectory,
 									  const String& filter, bool selectsDirectory, bool /*selectsFiles*/,
 									  bool isSaveDialogue, bool warnAboutOverwritingExistingFiles,
 									  bool selectMultipleFiles, FilePreviewComponent* extraInfoComponent)
 {
 	using namespace FileChooserHelpers;
 
+	const String title (title_);
 	HeapBlock<WCHAR> files;
 	const int charsAvailableForResult = 32768;
 	files.calloc (charsAvailableForResult + 1);
@@ -244269,26 +244271,29 @@ void FileChooser::showPlatformDialog (Array<File>& results, const String& title,
 			info.customComponent->enterModalState();
 		}
 
-		const int filterSpace = 2048;
-		HeapBlock<char> filters;
-		filters.calloc (filterSpace * 2);
-		const int bytesWritten = filter.copyToUTF16 (reinterpret_cast <WCHAR*> (filters.getData()), filterSpace);
-		filter.copyToUTF16 (reinterpret_cast <WCHAR*> (filters + bytesWritten), filterSpace);
+		const int filterSpaceNumChars = 2048;
+		HeapBlock<WCHAR> filters;
+		filters.calloc (filterSpaceNumChars);
+		const int bytesWritten = filter.copyToUTF16 (filters.getData(), filterSpaceNumChars * sizeof (WCHAR));
+		filter.copyToUTF16 (filters + (bytesWritten / sizeof (WCHAR)) + 1,
+							(filterSpaceNumChars - 1) * sizeof (WCHAR) - bytesWritten);
 
 		OPENFILENAMEW of;
 		zerostruct (of);
 
+		String localPath (info.initialPath);
+
 	  #ifdef OPENFILENAME_SIZE_VERSION_400W
 		of.lStructSize = OPENFILENAME_SIZE_VERSION_400W;
 	  #else
 		of.lStructSize = sizeof (of);
 	  #endif
 		of.hwndOwner = (HWND) parentWindow.getWindowHandle();
-		of.lpstrFilter = reinterpret_cast <WCHAR*> (filters.getData());
+		of.lpstrFilter = filters.getData();
 		of.nFilterIndex = 1;
 		of.lpstrFile = files;
 		of.nMaxFile = charsAvailableForResult;
-		of.lpstrInitialDir = info.initialPath.toUTF16();
+		of.lpstrInitialDir = localPath.toUTF16();
 		of.lpstrTitle = title.toUTF16();
 		of.Flags = flags;
 		of.lCustData = (LPARAM) &info;
diff --git a/src/native/windows/juce_win32_FileChooser.cpp b/src/native/windows/juce_win32_FileChooser.cpp
index a6f8ffef21..dc683f696e 100644
--- a/src/native/windows/juce_win32_FileChooser.cpp
+++ b/src/native/windows/juce_win32_FileChooser.cpp
@@ -96,7 +96,7 @@ namespace FileChooserHelpers
             if (ofn->hdr.code == CDN_SELCHANGE)
             {
                 FileChooserCallbackInfo* info = (FileChooserCallbackInfo*) ofn->lpOFN->lCustData;
-                FilePreviewComponent* comp = static_cast<FilePreviewComponent*> (info->customComponent->getChildComponent(0));
+                FilePreviewComponent* comp = dynamic_cast<FilePreviewComponent*> (info->customComponent->getChildComponent(0));
 
                 if (comp != 0)
                 {
@@ -130,8 +130,9 @@ namespace FileChooserHelpers
 
         void resized()
         {
-            if (getNumChildComponents() > 0)
-                getChildComponent(0)->setBounds (getLocalBounds());
+            Component* const c = getChildComponent(0);
+            if (c != 0)
+                c->setBounds (getLocalBounds());
         }
 
     private:
@@ -140,13 +141,14 @@ namespace FileChooserHelpers
 }
 
 //==============================================================================
-void FileChooser::showPlatformDialog (Array<File>& results, const String& title, const File& currentFileOrDirectory,
+void FileChooser::showPlatformDialog (Array<File>& results, const String& title_, const File& currentFileOrDirectory,
                                       const String& filter, bool selectsDirectory, bool /*selectsFiles*/,
                                       bool isSaveDialogue, bool warnAboutOverwritingExistingFiles,
                                       bool selectMultipleFiles, FilePreviewComponent* extraInfoComponent)
 {
     using namespace FileChooserHelpers;
 
+    const String title (title_);
     HeapBlock<WCHAR> files;
     const int charsAvailableForResult = 32768;
     files.calloc (charsAvailableForResult + 1);
@@ -230,26 +232,29 @@ void FileChooser::showPlatformDialog (Array<File>& results, const String& title,
             info.customComponent->enterModalState();
         }
 
-        const int filterSpace = 2048;
-        HeapBlock<char> filters;
-        filters.calloc (filterSpace * 2);
-        const int bytesWritten = filter.copyToUTF16 (reinterpret_cast <WCHAR*> (filters.getData()), filterSpace);
-        filter.copyToUTF16 (reinterpret_cast <WCHAR*> (filters + bytesWritten), filterSpace);
+        const int filterSpaceNumChars = 2048;
+        HeapBlock<WCHAR> filters;
+        filters.calloc (filterSpaceNumChars);
+        const int bytesWritten = filter.copyToUTF16 (filters.getData(), filterSpaceNumChars * sizeof (WCHAR));
+        filter.copyToUTF16 (filters + (bytesWritten / sizeof (WCHAR)) + 1,
+                            (filterSpaceNumChars - 1) * sizeof (WCHAR) - bytesWritten);
 
         OPENFILENAMEW of;
         zerostruct (of);
 
+        String localPath (info.initialPath);
+
       #ifdef OPENFILENAME_SIZE_VERSION_400W
         of.lStructSize = OPENFILENAME_SIZE_VERSION_400W;
       #else
         of.lStructSize = sizeof (of);
       #endif
         of.hwndOwner = (HWND) parentWindow.getWindowHandle();
-        of.lpstrFilter = reinterpret_cast <WCHAR*> (filters.getData());
+        of.lpstrFilter = filters.getData();
         of.nFilterIndex = 1;
         of.lpstrFile = files;
         of.nMaxFile = charsAvailableForResult;
-        of.lpstrInitialDir = info.initialPath.toUTF16();
+        of.lpstrInitialDir = localPath.toUTF16();
         of.lpstrTitle = title.toUTF16();
         of.Flags = flags;
         of.lCustData = (LPARAM) &info;