This is the expected behavior with this code.
. This will have the following benefits:
- you will not need to recreate server controls with each postback (as ASP requires for all dynamic controls)
- you will can avoid unnecessary postbacks
- without disposing the page (or, at least, the RadWIndowManager), the popups can keep their position and state even if other partial postbacks occur on the page.
If you need to get information from the server (e.g., the URL) I advise you examine this article to see how you can register a script that will do the job, so you can avoid disposing the RadWIndowManager: http://www.telerik.com/help/aspnet-ajax/window-troubleshooting-opening-from-server.html
. Thus, you can only pass an URL (and other parameters, if needed), to a function already created in the markup that will open the dialogs and set needed properties.
Alternatively, if you can declare the RadWindows in the RadWindowManager markup, you can try setting the PreserveClientState property of the manager to true. It will attempt to store the current bounds and size of the windows from the manager's collection to a cookie, but it is legacy functionality that may have issues. You can also consider using custom storage settings, as shown in this demo: http://demos.telerik.com/aspnet-ajax/persistence-framework/examples/custom-settings/defaultcs.aspx
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