Inverted Text in control buttons
 

I have an excel application programmed in VBA using Excel 97. When using the
application in a newer version of Excel (newer than 2000) on one particular
sheet the control button label text is inverted. Text switches to normal when
the button is clicked, then reverts to inverted when other buttons are
clicked. The function of buttons is not affected. Has anyone seen or have a
solution for this problem? Are there changes in functionality of specific
commands between the older and newer versions of VBA that would cause this?