Bug 460349, r+sr=roc

widget/src/cocoa/nsNativeThemeCocoa.mm

@@ -1231,6 +1231,8 @@ nsNativeThemeCocoa::DrawWidgetBackground(nsIRenderingContext* aContext, nsIFrame
   nativeWidgetRect.ScaleInverse(gfxFloat(p2a));
   nativeDirtyRect.ScaleInverse(gfxFloat(p2a));
   nativeWidgetRect.Round();
+  if (nativeWidgetRect.IsEmpty())
+    return NS_OK; // Don't attempt to draw invisible widgets.
 
   nsRefPtr<gfxContext> thebesCtx = aContext->ThebesContext();
   if (!thebesCtx)