Hello again,
I am just checking if you got this worked out or you still require any assistance or clarification on the matter.
If this is what you were looking for please verify the answer so it helps other users as well.
Hello stevemwall,
I have been looking into your issue and I suggest you add the following code in CellChanged event of your xamDataGrid to accomplish your goal.
DataRecordPresenter.FromRecord(e.Cell.Record).Background = Brushes.YellowGreen;
DataRecordPresenter.FromRecord(e.Cell.Record).FontStyle = FontStyles.Italic;
If you need any further assistance on this issue do not hesitate to ask.