When I have a couple Excel files that I opened through Excel's "open"
command, I have troubles when I then open a file through Windows Explorer.
I'm using Excel 2007 and have Windows Vista. If I open that third file using
Windows Explorer, sometimes the menus are disabled. I have to click alt+F4
in order to close the file because I can't even click the X on the
upper-right.

Is there a fix for this?