DBAdvGrid - New Row Dissapears when I move to the next cell


I have a DBAdvGrid connected to a datasource. teh data is displayed OK.
When i arroe down to "Add" a new row, the balnk row is added and allows me to enter data into any cell, however as soon as I tab/enter to teh next cell the whole row is removed.
My editpost mode is epRow

What settign am i missing that allows me to fills in all the Cells?

Thank you

I have retested this here with the demo under Demo\DBAdvGrid\CDSEditing where grid.Navigation.AppendOnArrowDown is set but I could not see such issue. Do you have more detail?