That is normal for the stealth chat mode in the UI. Reference post
322 that explains it.
The FetishNightfall.doc that came in the UI's zip file says to delete
eq2ui_mainhud_mainchat.xml
and rename
_simple_eq2ui_mainhud_mainchat.xml
to
eq2ui_mainhud_mainchat.xml
in order to replace it and revert back to the simple chat window that was used in version 3.4 and before so that you will not have any stealth scroll bar or input area.