Test Studio crashes when adding illegal Find Expressions to a Silverlight Appliction's find logic. Here are the steps to Reproduce: 

Go to:
 
1.	http://demos.telerik.com/silverlight/#GridView/CellEditTemplate
2.	Select Row
3.	Edit in live
4.	Add Subfilter
5.	Enter a valid Xaml Find Expression and element
6.	Then Validate (the application finds the element)
7. Click the plus sign
8.	Enter an illegal Find Expression or leave the field blank
9.	Then Validate 

Test Studio will then quit with the following error dialog: 

"An unexpected error occurred in Test Studio. The error has been reported to the Telerik team. Do you want to save your work?"