Thank you for writing.
As my colleague Peter mentioned, we are aware of this issue and we will address it in the upcoming Service Pack, which should be out at the end of November. If this time frame is not suitable for you, you can use one of the workarounds provided on the issue page: http://feedback.telerik.com/Project/154/Feedback/Details/141792-fix-raddropdown-popup-is-closed-when-click-the-scrollbar
As you to not want to apply the below proposed workaround to every instance of the control, you can use the second one, which is to inherit the control, apply the workaround there and replace the instances of RadDropDownList in your application with the derived type (you can use Search & Replace to apply the change easily). Here is the derived class for your convenience:
MyDropDownList : RadDropDownList
.PopupClosing += MyDropDownList_PopupClosing;
sender, RadPopupClosingEventArgs args)
Point relativeMousePositionInPopup = ((RadDropDownListElement)sender).ListElement.ElementTree.Control.PointToClient(Control.MousePosition);
args.Cancel = ((RadDropDownListElement)sender).ListElement.VScrollBar.ControlBoundingRectangle.Contains(relativeMousePositionInPopup);
I hope that you find this information useful. Should you have any other questions, do not hesitate to contact us.
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