Basically, you cannot check on the server if a certain page is displayed in an IFRAME (RadWindow is basically an IFRAME) or not. Such check can be done only on the client by using a slightly modified version of the GetRadWindow() function:
(window.radWindow) oWindow = window.radWindow;
(window.frameElement && window.frameElement.radWindow) oWindow = window.frameElement.radWindow;
wnd = GetRadWindow();
"This page is loaded in a RadWindow"
"The page is loaded in the browser"
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