Sometimes I forget that I've saved a file with multiple sheets selected, so when I later open the file, there are multiple active sheets. Then I make a change in one sheet (say, enter data into a cell), and therefore inadvertently make the same change to all the active sheets. Just did that for the umpteenth time, clobbering a lot of earlier work.

In my Excel 2010, the tabs of inactive sheets look very similar to the tabs of active sheets. The only difference is that the inactive tabs are a light gray, while the active tabs are a slightly lighter gray.

I would be most grateful if you could tell me how to adjust some setting/option so that the active tabs looked very dissimilar to the inactive tabs. Eg, inactive tabs could be dark gray, or purple, or something instantly visible.