diff --git a/gfx/thebes/gfxContext.cpp b/gfx/thebes/gfxContext.cpp
index 0ee0b3ebc1e..071c452672d 100644
--- a/gfx/thebes/gfxContext.cpp
+++ b/gfx/thebes/gfxContext.cpp
@@ -31,6 +31,8 @@
 using namespace mozilla;
 using namespace mozilla::gfx;
 
+UserDataKey gfxContext::sDontUseAsSourceKey;
+
 /* This class lives on the stack and allows gfxContext users to easily, and
  * performantly get a gfx::Pattern to use for drawing in their current context.
  */
@@ -1614,8 +1616,9 @@ gfxContext::PushGroupAndCopyBackground(gfxContentType content)
       gfxRect clipRect = GetRoundOutDeviceClipExtents(this);
       clipExtents = IntRect(clipRect.x, clipRect.y, clipRect.width, clipRect.height);
     }
-    if (mDT->GetFormat() == FORMAT_B8G8R8X8 ||
-        mDT->GetOpaqueRect().Contains(clipExtents)) {
+    if ((mDT->GetFormat() == FORMAT_B8G8R8X8 ||
+         mDT->GetOpaqueRect().Contains(clipExtents)) &&
+        !mDT->GetUserData(&sDontUseAsSourceKey)) {
       DrawTarget *oldDT = mDT;
       RefPtr<SourceSurface> source = mDT->Snapshot();
       Point oldDeviceOffset = CurrentState().deviceOffset;
diff --git a/gfx/thebes/gfxContext.h b/gfx/thebes/gfxContext.h
index 9c097433222..a589095f27e 100644
--- a/gfx/thebes/gfxContext.h
+++ b/gfx/thebes/gfxContext.h
@@ -708,6 +708,8 @@ public:
     void CopyAsDataURL();
 #endif
 
+    static mozilla::gfx::UserDataKey sDontUseAsSourceKey;
+
 private:
   friend class GeneralPattern;
   friend struct GlyphBufferAzure;
diff --git a/widget/cocoa/nsChildView.mm b/widget/cocoa/nsChildView.mm
index 2aa9faed9ed..fe54054bc9f 100644
--- a/widget/cocoa/nsChildView.mm
+++ b/widget/cocoa/nsChildView.mm
@@ -3377,12 +3377,14 @@ NSEvent* gLastDragMouseDownEvent = nil;
       gfxPlatform::GetPlatform()->CreateDrawTargetForSurface(targetSurface,
                                                              gfx::IntSize(backingSize.width,
                                                                           backingSize.height));
+    dt->AddUserData(&gfxContext::sDontUseAsSourceKey, dt, nullptr);
     targetContext = new gfxContext(dt);
   } else if (gfxPlatform::GetPlatform()->SupportsAzureContentForType(gfx::BACKEND_COREGRAPHICS)) {
     RefPtr<gfx::DrawTarget> dt =
       gfx::Factory::CreateDrawTargetForCairoCGContext(aContext,
                                                       gfx::IntSize(backingSize.width,
                                                                    backingSize.height));
+    dt->AddUserData(&gfxContext::sDontUseAsSourceKey, dt, nullptr);
     targetContext = new gfxContext(dt);
   } else {
     targetContext = new gfxContext(targetSurface);