diff --git a/mozilla/toolkit/components/autocomplete/src/nsAutoCompleteController.cpp b/mozilla/toolkit/components/autocomplete/src/nsAutoCompleteController.cpp
index 821f18d4db1..1b214f0063c 100644
--- a/mozilla/toolkit/components/autocomplete/src/nsAutoCompleteController.cpp
+++ b/mozilla/toolkit/components/autocomplete/src/nsAutoCompleteController.cpp
@@ -1212,7 +1212,8 @@ nsAutoCompleteController::ProcessResult(PRInt32 aSearchIndex, nsIAutoCompleteRes
 
 nsresult
 nsAutoCompleteController::PostSearchCleanup()
-{  
+{
+  NS_ENSURE_STATE(mInput);
   if (mRowCount) {
     OpenPopup();
     mSearchStatus = nsIAutoCompleteController::STATUS_COMPLETE_MATCH;