/*
The following example is taken from the docking demo. It
shows how the OnUnDock event handler of the conjoinment
docking site re-enables docking in the control that is
undocked (if it is a dockable form). In addition, when the
next to last docked control is undocked, the conjoinment
docking site sends itself a close message so that the last
docked control is undocked to its old position and size.
*/
void __fastcall TConjoinDockHost::FormUnDock(TObject *Sender, TControl *Client,
      TWinControl *NewTarget, bool &Allow)
{
  // Only 2 dock clients means the host must be destroyed and
  // the remaining window undocked to its old position and size.
  // Recall that OnUnDock gets called before the undocking
  // actually occurs.
  if (Client->ClassNameIs("TDockableForm"))
    dynamic_cast<TDockableForm *>(Client)->DockSite = True;
  if ((DockClientCount == 2) && (NewTarget != this))        // Self?
    PostMessage(dynamic_cast<TConjoinDockHost *>(this)->Handle, WM_CLOSE, 0, 0);
  UpdateCaption(Client);
}

{
The following example is taken from the docking demo. It
shows how the OnUnDock event handler of the conjoinment
docking site re-enables docking in the control that is
undocked (if it is a dockable form). In addition, when the
next to last docked control is undocked, the conjoinment
docking site sends itself a close message so that the last
docked control is undocked to its old position and size.
} 
procedure TConjoinDockHost.FormUnDock(Sender: TObject; Client: TControl;
  NewTarget: TWinControl; var Allow: Boolean);
begin
  // Only 2 dock clients means the host must be destroyed and
  // the remaining window undocked to its old position and size.
  // Recall that OnUnDock gets called before the undocking
  // actually occurs.
  if Client is TDockableForm then
    TDockableForm(Client).DockSite := True;
  if (DockClientCount = 2) and (NewTarget <> Self) then
    PostMessage(Self.Handle, WM_CLOSE, 0, 0);
  UpdateCaption(Client);
end;