Function list broken

Hello,

Something has happened in my Excel (2000 on XP) where the function
list dropdown from the toolbar (usually gives a short list of recently
used functions with a line to view more) no longer gives me access to
the full function list/dialog box. Instead, I have to go to the
Insert->Function menu, which is far less convenient. There are some
add-ins I use from third parties - could this be it? Any ideas on
what to try,

Thank you,
Jim