In Telerik UI for ASP.NET AJAX, the RadWindowManager is not mandatory to be present on the page in order to show a RadWindow. Using the RadWindowManager however, is still a convenient way to declare common properties for all RadWindow that will be created with it or are already declared in its Windows collection.
	
	
		On the client-side, the RadWindowManager takes care of:
	
	
		- creating and opening new windows
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			taking care of the radalert, radconfirm and radprompt dialogs - you must have a RadWindowManager control on your page in order to show these dialogs.
		
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			providing a reference to a RadWindow
		
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			group functions to allow RadWindows' manipulating at once (for example - minimizing, restoring or maximizing all RadWindows on the page)