Thank you for writing.
Before getting to your question, I would like to remind you that not providing us with the requested license information in the support thread "Master details in report
" (which you can find in "Your Account"), may result in denying support services for your account. This is why, I would like to kindly ask you to provide us with the requested information, so we can update your account status and continue providing you with undisturbed support services.
As to your question at hand, you should cancel RadDropDownList's PopupClosing event, for example:
sender, Telerik.WinControls.UI.RadPopupClosingEventArgs args)
(args.CloseReason == Telerik.WinControls.UI.RadPopupCloseReason.Mouse)
I hope this helps.
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.