Thank you for writing.
I have tried a scenario which involved loading a layout, which contained two or more groups. However, I am unable to reproduce the issue. On my side everything works as expected and all group headers respond on a mouse click operation.
Could you please open a new support ticket and send me a small sample project, which demonstrates your exact scenario? This will help me to investigate the issue further and provide you with accurate assistance.
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.