I have a radMenu on the main site.master form which shows on a page. The page has a radGrid with a button to open a radWindows that shows a report. When the radWindow opens everything works great but the radMenu shows through onto the Window.
You can determine which control to be shown above another one by setting
proper z-indexes. In your case in order to show the Radwindow above the RadMenu, either set a lower z-index to the RadMenu or set a bigger z-index to the RadWindow.