Notes:
If EnableAjax is enabled and EnabledLoadOnDemand is disabled, then dynamic UpdatePanels are created regardless of that property.
It is not recommended to modify that property within a posback, because it will trigger recreation of templates in all tab items, which may slow down performance.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2