autofilter problem

[Dave Murto]

I use an excel list as a chemical database in my lab. We use autofilter to
select for chemical name or other fields in the list. The file is stored on
a server and shared by several users. On one users machine, some odd
behavior has been observed in recent months. Sometimes the autofilter
controls disappear, leaving us unable to unselect the filter if the file has
been saved in that state. Generally the controls will reappear by double
clicking in the header row, but only on the offending machine, and it
sometimes takes repeated clicking.
This behavior may be related to another new feature of this file: A blue
box around the table, with a blue asterisk in the first empty row. It
appeared recently and I don't know why it's there.
Any explanation and potential fixes would be greatly appreciated.

thanks,
Dave