I have an Add-in that requires the first sheet to be visible to the user in
use. It uses columns of data on additional worksheets in the same workbook. I
the .xls file (prior to .xla conversion) I was succesfully using a compound
INDIRECT function to reference the data on these additional sheets. Now that
I have made an .xla file of it, first off, no sheets are visible. That's OK
as I've coded the first worksheet to be visible to the user but my INDIRECT
function won't work, it just gives a #REF error in the cells I use it.

My question is this; can I change the INDIRECT formula in the .xls file such
that when I make it an Add-in the formula still works and references the
other worksheets that are in the workbook but just not visible because the
file is now an Add-in? I get the feeling it's just a referencing issue but I
can't get the syntax right.

Thanks in advance,