Nic, if a thread is moved, surely it should no longer show in old location, no?!
Alright, since you asked, it's time for a little lesson in moderating the forum.
When a thread is moved, the moderator has the option to 'leave shadow topic in place'. If you choose that option, the thread will still show up in the section it was originally posted in. However, it will have a little arrow symbol next to it to indicate it's been moved.
If you uncheck that option, the thread will cease to show up in the original section.
When I first started doing this I unchecked the option cos I didn't see the point of it. Then someone complained that they had no longer been able to find their own thread. So I started leaving it checked for that reason.
Happy now?...