GPF caused by double clicking a cell to jump to its precedents.

Excel 2000:
formula in cell B2 of sheet "Sheet ABC" is of the form
=sum('Sheet XYZ'!$B$2:$B$100)

tools-Options-edit "Edit directly in cell" is unchecked.

when double click the cell it sometimes works OK and
selects the source data in the other sheet but
intermitently it crashes Excel.

Anyone got any ideas if this is a documented bug ?
It only seems to affect cells which have a function like
SUM() around the source data. It also seems to occur more
frequently if the source data is in a separate workbook.

Fergus