Determine when a control is selected in Expression Blend

I'm building an extension f开发者_StackOverflow社区or Expression Blend 4. My extension is visible as palette in Expression Blend.

When a user selects a ContentControl, i want to display some options in my extension pallette. So my question is how can i determine when a ContentControl (or another control) is selected? Thanks, Tim.

Kindly refer the following link for design-time interaction support.
http://msdn.microsoft.com/en-us/library/bb514646(v=VS.100).aspx