I have a workbook that was created in Excel 2003, and has been fine for the
past few months since I've moved to Excel 2007. About 2 weeks ago my
workbook shrunk so that it uses up only about 50% of the viewable area on the
work area window. Normally, you would be able to click on the Maximize
button, or double-click the Title Bar, to expand the sheet to the full window
size, but Maximize, Minimize, and Exit are not showing on the Title Bar of
the Worksheet at all, and double-clicking the Title Bar itself has no effect.
The only thing that appears different is that the Worksheet is marked as
being in Compatibility Mode.

Can anyone tell me how to get my worksheet expanded to use all of the
available screen area?

Thank you.