I have an add-in that runs when a user either first starts Excel or opens a
worksheet. The add-in checks any opened worksheet for several things (fonts,
tagged data, etc.).

The add-in is in the XLStart folder (running Windows XP, SP2, so the path to
the add in is C:\Program Files\Microsoft Office\OFFICE11\XLSTART).

When I open Excel, the add-in is visible and appears like any other
worksheet (except that it's named with an xla extension). The add-in is set
as read-only, so there's no real danger that users can change it, but I'd
like to know if there's a way to either keep the add-in from appearing
(best-case scenario), or failing that, at least minimize the add-in.

Thank you.