I have a grid bound to an XML data source. Some elements in the XML may be missing; in this case, the value of the corresponding field should be null. This is working fine when I use a string or number-type editor, but when using a DropDownList, if the element is missing from the XML, the grid cell remains blank after I select a value from the list. You can see this in this fiddle (try selecting a value in the bottom right cell).