The GridCheckBoxColumn cannot handle null values in a bit field. 

I would like to be able to bind the checkboxcolumn to a bit field that allows nulls. The checkbox should be checked when the value is true, unchecked when it is false, and filled when it is null.

The current solution is to use the RadButton inside a GridTemplateColumn and add custom togglestates, but this solution is not documented and it is very time intensive for something that should be quick and simple. It requires a lot of coding to update or insert a record.