The only time I could toggle the insert key was when I was editing the cell.
And just changing the selection took me out of edit mode.
I would find this very irritating, but I could use a worksheet event that would
put me into edit mode and toggle the Insert key. (This means that you'll be
editing the active cell each time you change the selection, right???)
If you want to try this on one sheet, you can rightclick on the worksheet tab
that should have this behavior and select view code. Paste this into the code
window that you see:
Option Explicit
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
SendKeys "{F2}{Insert}"
End Sub
Remember that hitting the Escape key will get you back to "normal".
If you really want to use this for all the worksheets in the workbook, you could
use a workbook event.
If you really want to use this for all the worksheets in any workbook, you'll
have to use an application event.
You can read more about events at:
Chip Pearson's site:
http://www.cpearson.com/excel/AppEvent.htm
http://www.cpearson.com/excel/events.htm
David McRitchie's site:
http://www.mvps.org/dmcritchie/excel/event.htm