When a page is ajaxified, the page lifecycle is executed the same way it would do with regular postbacks. All the events on the server are fired the same way in the same sequence. The main difference is that only certain part of the page is sent back on the client and only certain part of the page content is updated.
To improve the performce, you can make sure only the neccessary controls are visible, e.g. rendered after ajax.
If you observed that all controls, the ones you update with ajax and the ones you do not want to update after certain ajax request, this is probably due to an issue with the ajax configuration. If this is your case, please send us a sample illustrating your scenario so we can further check it.
the Telerik team
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