for future use of the server method.
Please also check for some global CSS rules or class overrides that may be interfering with the RadWindow. This is easiest done by removing all your custom CSS from the page and if the issue is gone then you can easily find the offending rule by re-adding them one by one.
As for the return type and handling the user input - please examine this article: http://www.telerik.com/help/aspnet-ajax/window-dialogs-confirm.html
. It explains that the result is returned in the callback function as a parameter and that it depends on the clicked button (true, false and null for the ok, cancel and [x] respectively). You can also see it in action in this online demo: http://demos.telerik.com/aspnet-ajax/window/examples/browserdialogboxes/defaultcs.aspx
To transfer this to the server you can either invoke an AJAX request
through the RadAjaxManager, or use the __doPostBack() function to either click on a hidden button (which one may depend on the value) that will execute the needed server-side mehod, or you can store the user response in a hidden field and look for it in the PageLoad server event.
the Telerik team
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