Bug 891904 - Un-schedule full spell check when checker is disabled; r=ehsan

extensions/spellcheck/src/mozInlineSpellChecker.cpp

@@ -625,6 +625,7 @@ nsresult mozInlineSpellChecker::Cleanup(bool aDestroyingFrames)
   }
 
   mEditor = nullptr;
+  mFullSpellCheckScheduled = false;
 
   return rv;
 }