I'm trying to modify the text size for RadTabItem headers for the entire application. If I set fontsize on the control itself it will apply to all children so I'm modifying the template to change the size on just the header content control.

I'm using the Metro theme set in the app.xaml.cs.

When I use Expression Blend to Edit a Copy of the template I would expect that the template that gets generated would be exactly the same as the default Metro radtabitem template but it's not. If I drop a tabcontrol, edit template (copy) and run the app the background of the active tab is no longer white. I thought that setting the Theme explicitly on the control and then generating a copy might make a difference but it didn't.

Is the suggested way to make changes like this to use Blend and generate a copy like I would for normal controls or do I have to include the Telerik theme project and modify the xaml directly there?