I am working on a fairly large application that refers to code in
several addins. Userforms are used, but there are no shapes, charts,
etc. on any worksheet.

My problem is that 'randomly', but usually some time after using the
main form (that can interact with cells on a worksheet) the test in
the formula bar textbox starts flickering like some code is caught in
an endless loop. I can interact with Excel at this point, but can't
naviagate to other workbooks or even close Excel without ending it's
process via TaskManager. The only way to get the flickering to stop is
to close Excel.

I have googled and searched this forum, but have found no expanation
or solution. I did see one promising thread that showed similar
symptoms when a worksheet cell was selected and then a shape was
selected. There was a snippet of code in that thread that caused the
text to flicker, but it would stop.

When this happens Excel consumes all of one of the dual core
processors on my computer. (50% total)
Also there is usually remnants of the user form in the dropdown box of
the formula bar.

Can any one help? I have O2007 SP2 installed.