The Telerik RadWindow component is similar to the RadDock component. Both create floating regions on your page that the user can move around, collapse, pin, etc. Both let you specify the command buttons that appear on the title bar, and let you assign client event handlers to respond to user actions. Both have an appearance that you can customize with skins.
However, there are some significant differences between RadWindow and RadDock:
RadWindow provides support for using the window as a dialog, including the ability to give the window a modal state, to pass parameters to the window, and to respond to results using a callback function.
RadDock windows can be docked to docking regions on the page, where they still display their content. RadWindow does not support this same behavior. Instead, it allows for minimization into minimize zones.
RadWindow supports an OnClientPageLoad event when the content in the window loads. Because RadDock does not load external content, it has no analogous event.