Hide MDIChild form's caption bar

Change CreateParams procedure, like this example:

type
  TForm2 = class(TForm)
  private
    procedure CreateParams(var Params: TCreateParams); override;
    { Private declarations }
  public
    { Public declarations }
  end;
...
procedure TForm2.CreateParams(var Params: TCreateParams);
begin
  inherited CreateParams(Params) ;
  Params.Style:=Params.Style and (not WS_CAPTION) ;
end;