--- a/ipc/glue/WindowsMessageLoop.cpp
+++ b/ipc/glue/WindowsMessageLoop.cpp
@@ -496,16 +496,18 @@ UnhookNeuteredWindows()
 {
   if (!gNeuteredWindows)
     return;
   PRUint32 count = gNeuteredWindows->Length();
   for (PRUint32 index = 0; index < count; index++) {
     RestoreWindowProcedure(gNeuteredWindows->ElementAt(index));
   }
   gNeuteredWindows->Clear();
+  delete gNeuteredWindows;
+  gNeuteredWindows = NULL;
 }
 
 void
 Init()
 {
   // If we aren't setup before a call to NotifyWorkerThread, we'll hang
   // on startup.
   if (!gUIThreadId) {