Color of grouped sheets

I have just recently moved from Excel 2000 to Excel 2003. I am having some difficulty when selecting multiple sheets (Grouping). In 2000 the grouped sheets would all be highlighted as to easily see that multiple sheets were selected, but in 2003 the sheets are no longer highlighted. They just look the same as the unselected sheets. Does anyone know if there is a setting to automatically highlight the sheets that have been selected?

Actually I figured out what the problem was. The default display theme (Control Panel) is Windows XP which puts Excel in a very light shade of tan. This shade of tan is very hard to distinguish from white, so the highlighted sheets are not standing out whatsoever. I changed my theme to Windows Classic and Excel is now back to a shade of gray. I can now see the highlighted sheets very distinctly.