In my model I have a nullable foreign key (DocumentCausalID) and the foreign object (DocumentCausal).
I'm using the default "GridForeignKey" editor template to choose the value using the DropDownList.
I've edited the default "GridForeignKey" adding the OptionLabel so I can choose a null value.
When I select the null value it update the row correctly, but the next time if I select a not-null value on the same row it doesn't work: it doesn't enter into the Update function of my controller.
Can you help me? (I've attached my Model, View and the Editor Template)