title: Prevent telerik window from Closing in onClose client event
body: <p>I am trying to display a confirm dialog when a user tries to close a window by click the 'X' in the top right corner. If the user goes for 'OK' option,  I would like to continue closing the window but if the user presses the 'Cancel' button I would like to prevent the window from closing. Is there a way to do that?</p>