I have a thread that I want to delete so I proceed and enter "test1" as the reason. Then even when the thread is already deleted I'm still allowed to "delete" it again. This doesn't make sense. In vBulletin you get an error message stating: "you didn't selected any valid posts".
Also, if you try to "delete" it again and specify "test2" as the reason the system keeps the original reason of the first deletion. This is weird.