By default, the ExtendedVisible property is "Visible", which specifies that the split bar is using the "Visible" property of the extended control to show or hide a component on the container. The Visible property of an extended control shows or hides object. Extended controls may be implemented by OLE control containers to provide a wrapper for contained controls. The HideOnLimit property gets or sets a value that indicates whether the splitting objects are hidden when the split bar is closed to its limit. The LimitLT property specifies the expression that determines the limit to drag the splitter to left/top side of its container. The LimitRB property specifies the expression that determines the limit to drag the splitter to right/bottom side of its container. 

The /COM version may use one of the following to show / hide the object:

• using the Visible property of the extended control, as indicated by the ExtendedVisible property
• using the ShowWindow API, if the handle of the window can be detected using the IOleWindow::GetWindow, from obj parameter ( VC++ environment )
• using the ShowWindow API, if the obj refers to a handle of the window ( Delphi enviroment )

The /NET version shows or hides the objects:

• using the Visible property of the Control object (System.Windows.Forms)

The ExtendedVisible property is not available for /NET version.