The default style of RadComboBox specifies MinHeight=26. If you are trying to set Height lower than 26, you might also need to set the MinHeight property. For example:
<telerik:RadComboBox MinHeight="20" Height="20" />
If this is not the case, I will need more information about the page containing RadComboBox, or in the best case a simple project which demonstrates the problem.
I will try to avoid this peculiarity in the next official build of RadControls for Silverlight. I will be happy to get your feedback on that, or any other problem in the controls you have found. Your points have been updated.
Valeri Hristov (Silverlight Team)
the Telerik team
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