diff --git a/layout/forms/nsComboboxControlFrame.cpp b/layout/forms/nsComboboxControlFrame.cpp
index f69198cc78..5a94389395 100644
--- a/layout/forms/nsComboboxControlFrame.cpp
+++ b/layout/forms/nsComboboxControlFrame.cpp
@@ -1040,6 +1040,9 @@ nsComboboxControlFrame::HandleRedisplayTextEvent()
   mRedisplayTextEvent.Forget();
 
   ActuallyDisplayText(true);
+  if (!weakThis.IsAlive())
+    return;
+
   // XXXbz This should perhaps be eResize.  Check.
   PresContext()->PresShell()->FrameNeedsReflow(mDisplayFrame,
                                                nsIPresShell::eStyleChange,