delphi devexpress how to dock Tform in dxdockpanel at runetime (SDI project)

Question

I have an SDI project, I want to dock a form in TDxdocpanel dynamyqe in C# it's easy

dxdocpanel.contols.add(myform);

However in Delphi I find a lot of difficulty,especially with this error

project raised exception class EInvalidOperation with the message 'Control 'TdxDockPanel($0CD5E660)' has no parent window. Path : f_main .TdxDockPanel($0CD5E660)'.

dockme(f_matriels);


procedure Tf_console.dockme(mform:tform); 
var 
Apanel:TdxDockPanel; bts:TdxCaptionButtons;
begin
Apanel:=TdxDockPanel.Create(self);   
Apanel.CaptionButtons:=[cbClose];  
Apanel.AllowFloating:=false;  
Apanel.DockTo(dxDockSite1,dtClient,0);   
mform.Dock(Apanel,mform.Canvas.ClipRect);   
Apanel.show;


end;