停留在窗体下面

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs;

type
  TForm1 = class(TForm)
  private
    { Private declarations }
    procedure WMNCActivate(var Msg: TWMNCActivate ); message WM_NCACTIVATE;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.WMNCActivate(var Msg: TWMNCActivate );
begin
  Msg.Result:=0;
end;

end.