I have many Excel files with buttons, checkboxes and other controls
created with Excel 2003.
I use them with older and newer versions of Excel, in different
operating systems, and they usually work well.
But sometimes when I click a button the macro starts and that button
shrinks one pixel.
Sometimes keeps shrinking at each click, sometimes shrinks only the
first click, sometimes only some button shrink and other buttons keep
their size.
Yesterday I was using a file in the office computer and it was ok.
Today I connected to the office computer with remote desktop, the file
was still open, and the buttons were shrinking for the first 2 hours
(I kept closing and reopening the file, but the buttons kept
shrinking), and now they stopped shrinking.

Does anybody know the reason of this weird behavior?

Thanks,
Stefano