Can't Edit Contents of Protected Worksheet
 

I'm using Excel 2003, and I can't seem to edit the contents of an unlocked
cell when I protect the worksheet. Hitting F2 in these cells deletes the
content of the cells. I am allowed to enter in new data, but I would prefer
that F2 would work as it does with unprotected worksheets (i.e., and allow me
to modify the cell's existing information). I've done a lot of testing on
this, including on other machines, even other versions (2000 and 2002). Is
this really an "undocumented feature" or am I losing my mind?