Could you ensure that both a RadAjaxManager and a RadAjaxPanel were not used for ajaxifying the page contents? In such cases double ajaxification will occur which will break the logic thus preventing the popup from opening(more information is available here
). Other than that I can not think of anything else that can cause this problem. That said I would like to ask you to share with us the contents of the page(markup and code-behind) so we could further examine the scenario.
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