I am fairly new to using the RadWindow control, and most of the code was written by someone else originally, so I hope this makes sense. Right now we have a page that is in a masterpage, and from that page, there are buttons which use the OpenWindow function to open a window in the content page that consists of TextBoxes and some other controls. I need to be able to check for a condition if the user tries to close the window, popup an error if a condition is not met, and keep the window open. This functonality is needed to keep the functionality similar to the previous version of our application that was written in Access. I saw something about that server side code can still run while the alert is up, so I am thinking that I won't be able to use the alert you have with the control. Is there a way to do this with the current version of the RadWindow? If so, would the orginal page or windowed page need to handle that logic?