Thank you for the writing.
The described behavior is actually a behavior of .NET Framework - you can try this with a MIcrosoft ComboBox. As far as we are aware, there is no elegant way to change this behavior.
If you have additional questions, feel free to contact me.
the Telerik team
Q1’11 SP1 of RadControls for WinForms is available for download
; also available is the Q2'11 Roadmap
for Telerik Windows Forms controls.