I'll give the support team at Syncfusion credit--they do seem to respond quickly to help you out.
But I'd give the development team there a failing grade. They seem to be prone to deploy rather buggy controls for WPF use.
Seems getting "NullReferenceException" is commonplace with their controls. And I just stumbled onto a stupid one--using their DateTimeEdit control and setting the MinDateTime attribute causes the control to display "01/01/0001" as its datetime value. These kind of bugs are extremely annoying when you are trying to get a job done. They're so bad that I don't know how they get away with charging for them when so many open-source and non-buggy alternatives are available. Had I been give the ability to choose which controls to use, Syncfusion would never have been considered.
Fortunately, I stumbled onto http://wpf.codeplex.com/Release/ProjectReleases.aspx?ReleaseId=29117. There is a DatePicker control there that'll work for me--and there's probably a large number of other controls. Especially since Syncfusion is about as crappy as it comes--try finding what you need without asking their support department--I'm going to trash the Syncfusion control usage wherever possible.
