Hi ...

My brother made me a workbook a year ago or so.
Today I found out that a formula was linked to a cell in a hidden worksheet. After unhiding it, I was astonished to find out a formula had a reference to to an completely empty cell 'fisk!a13', but still the formula worked correctly.
How come?
How can I get that cell to show its content?

In advance thanks
Regards
Tresfjording