Make it possible to override the functionality of keystrokes in the control. A useful case is when placing the control inside RadGridView's CellEditTemplate and wanting to leave cell editing mode by pressing the escape keyboard key.
Issue was duplicated with "Esc KeyDown is handled even when the popup is closed." which can be found here: http://feedback.telerik.com/Project/143/Feedback/Details/113724-esc-keydown-is-handled-even-when-the-popup-is-closed