RachelRachel 133k6767 gold badges315315 silver badges510510 bronze badges two 3 Rachel, you might be a good looking genius!!! And that i am an idiot. Thanks a great deal for the solution. I used to be binding to self and did not have a 'ConfigurationModel' property in my IncrementingTextBox class. MaartenMaarten https://share.evernote.com/note/3d05d401-bf05-0356-8ef1-7f062145b888