diff --git a/dlls/msctf/threadmgr.c b/dlls/msctf/threadmgr.c
index 9fb1b5d42e..4b21b56e0a 100644
--- a/dlls/msctf/threadmgr.c
+++ b/dlls/msctf/threadmgr.c
@@ -389,7 +389,9 @@ static HRESULT WINAPI ThreadMgr_SetFocus( ITfThreadMgr* iface, ITfDocumentMgr *p
 
     TRACE("(%p) %p\n",This,pdimFocus);
 
-    if (!pdimFocus || FAILED(IUnknown_QueryInterface(pdimFocus,&IID_ITfDocumentMgr,(LPVOID*) &check)))
+    if (!pdimFocus)
+        check = NULL;
+    else if (FAILED(IUnknown_QueryInterface(pdimFocus,&IID_ITfDocumentMgr,(LPVOID*) &check)))
         return E_INVALIDARG;
 
     ITfThreadMgrEventSink_OnSetFocus((ITfThreadMgrEventSink*)&This->ThreadMgrEventSinkVtbl, check, This->focus);