Table view marks all numeric columns as dirty

Hello,

I have a table view where I also allow users to save changes. In my code I'm checking for the cells that have changed using "If tvr.Item("Bonus").IsDirty()". This seems to work fine for non-numeric columns, however, I find that for the numeric columns the cells are always marked as dirty even if they are not changed. I tried different things, e.g. marking the column as decimal data type "tv.Columns(7).DataType = XFDataType.Decimal" but so far no luck.

Do you have any advise how this can be solved?

Thanks, Volker