It seems the November patch for Excel has an unwelcome side effect – It totally messes with screen updating and causes content from multiple sheets to appear mixed up.
So if you get automatic updates, or just like being bang up to date, and in the last few days have started to have unusual screen updating issues check out this link:
That page also tells you how to remove the patch to test (Add/Remove programs).
Note this issue may affect 2007 and 2003 as the patch is for both versions.
The patch fixes some security vulns so I guess thats the choice you make, more secure with flaky screen, or less secure with smooth screen updating.
I made my choice a long time ago when I stopped applying patches because they just broke stuff or ripped out useful functionality.
Anyone else suffering from this issue?