MainForm上加Panel,把Panel的DockSite设为True, 把窗口FB_orderManage的DragKind设为dkDock,  DragMode设为dmAuromatic 

在MainForm中调用： 

FB_orderManage:= TFB_orderManage.Create(self);

FB_orderManage.ManualDock(RzPageControl1,nil,alclient);

FB_orderManage.FormStyle:=fsStayOnTop;

FB_orderManage.Show;

FB_orderManage.Visible := True;