Thank for contacting Syncfusion Support.
We have checked your query “user control set state Hidden, not need to raise load event of base class”. In DockingManager we have changed the visibility for the parent container of the docking child(user control) when its dock sate is Hidden. But we didn’t perform any operation of the content(user control) added to the parent container. So, it is not possible to restrict the loaded event of the user control when it added as docking manager child.