Creates a new dock panel and docks it to the current dock panel.
A DockPanel object representing the dock panel created by this method.
If the current dock panel has no child panels, a split container which owns the current and newly created panels is automatically created. Otherwise, if the current panel contains any dock panels (children), a newly created panel is added to the collection of panels owned by the current panel.
You can also use the dock manager's DockManager.AddPanel method to create and add a panel to the form (user control).