The scripts of the controls are not combined in a single request, when the web.config key Telerik.ScriptManager.TelerikCdn.CombinedResource has value Enabled: Steps to reproduce 1. Ad the following configuration in the web config and open a page containing RadControl. <appSettings> <add key="Telerik.ScriptManager.TelerikCdn" value="Enabled"/> <add key="Telerik.ScriptManager.TelerikCdn.CombinedResource" value="Enabled" /> </appSettings> Result: The scripts are not combined. Workaround: Enable the script combining in the ScriptManager declaration: <telerik:RadStyleSheetManager runat="server"> <CdnSettings CombinedResource="Enabled" TelerikCdn="Enabled" /> </telerik:RadStyleSheetManager>