I am not exactly sure what the problem is since i am already using the DLLs that you have mentioned. I'm not quite sure which version of RadControls that we use, I only know that it's for silverlight 3, though I believe it's the latest build of SIlverlight 3 RadControls. The error that I have mentioned above
sender, System.Windows.Input.TextCompositionEventArgs e)
pops up when the intellisense generates the event handler for me with no code in the function That Is all the code that I have.
All i'm ultimately trying to do is to keep the dropdown menu open when the user is typing into the RadComboBox