LockDialog
This dialog allows you to lock a file. You bring it up either using "Context Menu on a file -> Subversion -> Lock..." or when the ?svn:needs-lock property has been set.
You can select what files should be locked from the top control. In the "Lock Message" field you can enter a message that other people see when they retrieve the lock information. The "Steal Lock" checkbox can be used to force locking the file(s), invalidating the locks taken by other users.
If you have any more question on this dialog, or suggestions on how to improve this content, please bring them up at the AnkhSVN Dev Mailing List