Assuming you've indeed gone back to the default UI (deleted the custom one and/or removed the reference to it from your eq2.ini), the thing that leaps to mind is your servername_charname_eq2_uisettings.xml might be storing a change that was caused by using that custom UI.
What I would do is try renaming that uisettings file for your character; that will reset all windows to their defaults. If that doesn't work, then run a full file scan in the patcher just to be safe.
__________________
|