>show when going to reply. Don't you think it should?

Those are not appearing when replying. They only appear at the creation of a thread.

>I just went to reply to a thread titled "Windows XP Locking", having noticed that only 3 of the 4 dropdowns showed content (there was no "Network" item so I guess it meant no network involved.

When reading a message, only for the related forums and only for the related selected item it will show.