You could use RadAjaxManager added programmatically on the main page like this:
sender, EventArgs e)
RadAjaxManager manager = RadAjaxManager.GetCurrent(Page);
Then in each DNN Module you could get reference to this main RadAjaxManager using the RadAjaxManager.GetCurrent(Page) method and add the needed settings programmatically as shown here:
I hope this helps.
All the best,
the Telerik team
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