Backing out previous change, didn't notice the orange, sorry:(

uriloader/exthandler/nsExternalHelperAppService.cpp

@@ -1976,9 +1976,6 @@ nsresult nsExternalAppHandler::OpenWithApplication()
   // if a stop request was already issued then proceed with launching the application.
   if (mStopRequestIssued)
   {
-    // make the tmp file readonly so users won't edit it and lose the changes
-    mFinalFileDestination->SetPermissions(0400);
-
     rv = mMimeInfo->LaunchWithFile(mFinalFileDestination);        
     if (NS_FAILED(rv))
     {