diff --git a/dlls/msctf/tests/inputprocessor.c b/dlls/msctf/tests/inputprocessor.c
index 38c591ea409..f8ec492f7f0 100644
--- a/dlls/msctf/tests/inputprocessor.c
+++ b/dlls/msctf/tests/inputprocessor.c
@@ -2287,6 +2287,7 @@ static void test_AssociateFocus(void)
     ITfDocumentMgr *dm1, *dm2, *olddm, *dmcheck, *dmorig;
     HWND wnd1, wnd2, wnd3;
     HRESULT hr;
+    ULONG ref;
 
     ITfThreadMgr_GetFocus(g_tm, &dmorig);
     test_CurrentFocus = NULL;
@@ -2428,10 +2429,20 @@ static void test_AssociateFocus(void)
     processPendingMessages();
     SetFocus(wnd1);
     processPendingMessages();
-    test_OnSetFocus = SINK_UNEXPECTED;
+
+    hr = ITfThreadMgr_AssociateFocus(g_tm,wnd2,dm2,&olddm);
+    ok(SUCCEEDED(hr),"AssociateFocus failed\n");
+
+    /* Vista doesn't return NULL */
+    if (olddm) ITfDocumentMgr_Release(olddm);
+    ref = ITfDocumentMgr_Release(dm2);
+    ok(ref == 0, "incorrect DocumentMgr ref %d\n", ref);
+
+    hr = ITfThreadMgr_AssociateFocus(g_tm,wnd2,NULL,&olddm);
+    ok(SUCCEEDED(hr),"AssociateFocus failed\n");
+    ok(olddm == NULL, "incorrect old DocumentMgr returned\n");
 
     ITfDocumentMgr_Release(dm1);
-    ITfDocumentMgr_Release(dm2);
 
     test_CurrentFocus = dmorig;
     test_PrevFocus = FOCUS_IGNORE;
diff --git a/dlls/msctf/threadmgr.c b/dlls/msctf/threadmgr.c
index 2c208fbc04f..77cf47ca4f6 100644
--- a/dlls/msctf/threadmgr.c
+++ b/dlls/msctf/threadmgr.c
@@ -1530,6 +1530,8 @@ void ThreadMgr_OnDocumentMgrDestruction(ITfThreadMgr *iface, ITfDocumentMgr *mgr
 {
     ThreadMgr *This = impl_from_ITfThreadMgrEx((ITfThreadMgrEx *)iface);
     struct list *cursor;
+    BOOL found = FALSE;
+
     LIST_FOR_EACH(cursor, &This->CreatedDocumentMgrs)
     {
         DocumentMgrEntry *mgrentry = LIST_ENTRY(cursor,DocumentMgrEntry,entry);
@@ -1537,8 +1539,16 @@ void ThreadMgr_OnDocumentMgrDestruction(ITfThreadMgr *iface, ITfDocumentMgr *mgr
         {
             list_remove(cursor);
             HeapFree(GetProcessHeap(),0,mgrentry);
-            return;
+            found = TRUE;
+            break;
         }
     }
-    FIXME("ITfDocumentMgr %p not found in this thread\n",mgr);
+    if (!found) FIXME("ITfDocumentMgr %p not found in this thread\n",mgr);
+
+    LIST_FOR_EACH(cursor, &This->AssociatedFocusWindows)
+    {
+        AssociatedWindow *wnd = LIST_ENTRY(cursor,AssociatedWindow,entry);
+        if (wnd->docmgr == mgr)
+            wnd->docmgr = NULL;
+    }
 }