--- a/widget/cocoa/nsChildView.mm
+++ b/widget/cocoa/nsChildView.mm
@@ -2410,17 +2410,17 @@ nsChildView::UpdateTitlebarCGContext()
 // them works as expected - but their visual representation is only drawn into
 // the normal window buffer, and the window buffer surface lies below the
 // GLContext surface. In order to make the titlebar controls visible, we have
 // to redraw them inside the OpenGL context surface.
 void
 nsChildView::MaybeDrawTitlebar(GLManager* aManager)
 {
   MutexAutoLock lock(mEffectsLock);
-  if (!mIsCoveringTitlebar || mIsFullscreen) {
+  if (!mIsCoveringTitlebar || mIsFullscreen || mTitlebarRect.IsEmpty()) {
     return;
   }
 
   LayoutDeviceIntRegion updatedTitlebarRegion;
   updatedTitlebarRegion.And(mUpdatedTitlebarRegion, mTitlebarRect);
   updatedTitlebarRegion.MoveBy(-mTitlebarRect.TopLeft());
   mUpdatedTitlebarRegion.SetEmpty();