#286207

r=mkaply, sr=blizzard (platform specific)
From Rich Walsh - Hack workaround for OS/2 crash caused by the fix for 125386


git-svn-id: svn://10.0.0.236/trunk@170695 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/widget/src/os2/nsDragService.cpp

@@ -137,6 +137,9 @@ NS_IMETHODIMP nsDragService::InvokeDragSession(nsIDOMNode *aDOMNode,
                                             nsIScriptableRegion *aRegion,
                                             PRUint32 aActionType)
 {
+  if (mDoingDrag)
+    return NS_ERROR_UNEXPECTED;
+
   nsBaseDragService::InvokeDragSession ( aDOMNode, aTransferables,
                                          aRegion, aActionType );
   mSourceDataItems = aTransferables;