I use AjaxUpdatedControl to update divTemplatePreview with LoadingPanel2. But the resulting HTML codes contain duplicate <div> for id = ctl00_ContentArea_ctl00_ContentArea_divTemplatePreviewPanel as follows.
Choose one of the Two and use only that to enable AJAX for the Controls. For an in-depth explanation of how the RadAjax controls work, check out the Understanding AJAX Controls Knowledge-Base article.
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