Problem with "Search box" in Help window
 

We are using Excel 2003 on XP. This problem is occuring for all users.

When you click Help-Microsoft Excel Help, and try to type in the Search for:
box under Assistance, the text is inserted into the spreadsheet instead.

The only way you can manage to enter any text into this box is to copy it,
then right-click paste it into that box (Edit-Paste and Ctrl+V do not work)

I can't find anything in the kbase (except for the tip about pasting).

What is up with this?