Hi, I have observed similar behaviour as James desribed. I have set AutoCreateColumns=False, not defined CellEditor and editing works only while string property was not null. If  property was null, CellEditor do not shows. I have modified my data objects using ValueConverter to convert automatically null to String.Empty because Oracle ...

I need to have some Cells in grid to be ReadOnly and some to be editable. I have found that settings property ReadOnly=''True'' for DataCell has no influance, and there is still posiible to edit content of cell (for test I use default editor). I use Style like this<Style TargetType=''{x:Type xcdg:DataCell}''><Setter Property=''ReadOnly'' ...