Templates in extended Silverlight controls

i am looking to extend a third party control, it is a ComboBox (so it isn't the standard Silverlight one, but that shouldn't matter for this question). To do this, i add a new template control to my controls project, then i change the new control to inherit from ComboBox instead of Control. A style has been created for me in the generic.xaml file, so i delete the default border stuff that was inserted, and then add a property setter for t开发者_如何转开发he PopupTemplate.

My problem is that when doing it this way, the combobox doesn't (visibly) render in the silverlight application anymore. However, in the constructor of my extension if i comment out the line

this.DefaultStyleKey = typeof(MyComboBox);

and put the PopupTemplate xaml bit in the main silverlight page, it renders correctly. I want the popup template to be declared within the control library, but does this mean that i also have to define the regular Template property? Am i wrong in thinking that anything i don't explicitly specify should just be inherited from the base control?

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A control can only have one default style. You need to copy the entire default style of the base control into the Generic.Xaml for you new MyComboBox then adjust it accordingly.