I’ve been busy sharpening my Silverlight skills and created my very own button, complete with VSM.

The button (‘rjButton’) inherits from contentControl and in the project there is a generic.xaml which defines a default look for the button, including VSM definitions and state transitions.
When loading up my solution in Blend, I can happily get the rjButton in my page. It looks correct. However, when I ‘Edit a copy’ of the template, nothing shows up!! Funnily enough, when I use ‘Create empty’, the correct states do show up.

I was unable to google-fix the problem. I would guess that when you use ‘create empty’, Blend just looks at the attributes on your class and shows the correct states. When you ‘Edit a copy’, Blend looks for the template and can not find any. Somehow it is unaware of the link to the style in generic.xaml, and it creates an empty style.

I’ve double checked the behavior with the TabControl, which is also a control that is defined in an external control, and it works the same.
I'm not sure why controls included in the framework do work correctly. I've taken a look with reflector and I've seen nothing out of the ordinary.

You can work around this by naming the style and explicitly tell the control to use the style. But then again, it might be easier to just copy the style (use David's excellent style browser here).

If you know what is going on, leave a comment!

[update: jasonxz knows: I was informed, today, that Blend does not, yet, support the "edit a copy" functionality of a Template that is not defined in System.Windows.dll. Thnx! ]