Unable to edit text boxes after coverting to excel 2007
 

I have a spreadsheet that was developed with Excel 2003. The spreadsheet
contains many text boxes. When I open this spreadsheet with Excel 2007 (in
Vista) I am unable to edit any of the text boxes. The handles do not appear
as expected when I click on the text.

If I create a new text box (in Excel 2007) these new text boxes work fine,
the handles are available and I can resize and edit. It is only the old ones
that were created in Excel 2003 that cannot be edited.

I have tried saving the spredsheet as a 2003 (.xls) and 2007 (.xlsx) then
opening using Excel 2007. Neither allow me to edit the text boxes. I have
opened both of these with Excel 2003 (in XP) and again neither allow me to
edit the text boxes.

How can I edit these text boxes?
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Thanks for your help.