When using a property grid, I have a DataTemplateSelector for properties that require my custom control to edit. Upon initializing my control, I need a view model set, so I use AutoBindBehavior.UpdateBindingOnElementLoaded for that purpose. Several times I have renamed a convenience setter for a property in my view model without renaming the corresponding dependency property, thus I was violating convention but nothing else. Each time I did that, I would get a null reference exception. I spent many hours trying to figure out what I did wrong.
I would be SOOO helpful if the exception in this case said "unable to find dependency property X" I would've know exactly what I did wrong...