Flush the gdi batch in NtGdiDeletObjectApp to make sure we don't try to do stuff with deleted objects later. This fixes some problems with Firefox.

svn path=/trunk/; revision=38501

reactos/subsystems/win32/win32k/objects/dc.c

@@ -1090,6 +1090,8 @@ BOOL
 APIENTRY
 NtGdiDeleteObjectApp(HANDLE  DCHandle)
 {
+  /* Complete all pending operations */
+  NtGdiFlushUserBatch();
 
   if (GDI_HANDLE_IS_STOCKOBJ(DCHandle)) return TRUE;