Hi.

I have a spreadsheet which has one worksheet (Analysis) where the rows in
one column reference the rows on a second worksheet using a simple worksheet
reference notation, for example:
='Retail Price List'!A1

I use ADO.NET (using ASP.NET / C#) to populate the values of the 'Retail
Price List' worksheet and when I do so, the values from the 'Retail Price
List' worksheet show up correctly on the 'Analysis' worksheet.

However if I add a custom ribbon to the excel document, the ='Retail Price
List'!A1 type references no longer reflect the data on the 'Retail Price
List' worksheet. Instead it shows '0' in the cell that contains the ='Retail
Price List'!A1 reference, even though the A1 cell on the Retail Price List
worksheet contains a value. If I edit the cell that contains the ='Retail
Price List'!A1 reference (i.e. hit F2 and then Enter without making any
changes), the value shows up.

The only difference between this working correctly or not is that it stops
working correctly after I add a custom ribbon using the Office Custom UI
Editor tool.

I am using Excel 2007. The excel file format is .xlsm.
In C# I use the 'Microsoft.ACE.OLEDB.12.0' ADO.NET driver for Excel.

Does anyone have an idea for why the cell references are not correctly
reflected?

Thanks