The best feature in WPF, which I very appreciate, is that WPF is a real O.O framework. Its services are exposed as a pile of polymorphic types, having common base classes and interface implementation. As every aspect in the real life (especially in software), not everything is perfect and so is WPF.
One of the things that I'm a little disappointed with is Control Templates.
The big Why
Control Template is a strong mechanism in WPF. With Control Templates, a control’s logic is totally separated from its view. A Control Template is actually the control's view-factory. It is responsible for defining the structure of the view. For example, it is possible to replace a radio-button control view but still keeping its logic, by just replacing its control-template with a new one.
The problem is "replace it with a new one", which means: You can't reuse a template, unless you are copying it!
So what's wrong with copying the template? The ultimate answer is Maintenance!
What a control template writer should do when he/she based its template on one of the WPFs themes, let say Luna, and then Microsoft find a bug in this theme?
Having the patch will not resolve the problem since the control template writer has copy it, remember?
The same thing will happen to other controls which are based on the same template, or others.
Having my point clear, I will leave this question open to the Microsoft WPF team. I hope that they will find a workaround for this issue in the next release.