TDockTree = class(TInterfacedObject, IDockManager)
class PASCALIMPLEMENTATION TDockTree : public System::TInterfacedObject
TDockTree handles the tasks of inserting and removing controls when they are docked to or undocked from a windowed control, including details such as positioning controls and any painting that is associated with docking operations. TDockTree implements the type of docking zones that appear in the IDE, with splitters that let users resize the docking zones, and grab regions where users must click to start an undock operation.
If an application does not explicitly assign a value to a windowed control's DockManager property, then the windowed control uses TDockTree to handle docking operations (if the UseDockManager property is true).