unit Unit1; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs; type TForm1 = class(TForm) protected procedure WMSysCommand(var Message: TWMSysCommand); message WM_SYSCOMMAND; end; var Form1: TForm1; implementation {$R *.dfm} procedure TForm1.WMSysCommand(var Message: TWMSysCommand); begin case Message.CmdType of SC_CLOSE: begin Perform(WM_SYSCOMMAND, SC_MINIMIZE, 0); Exit; end; end; inherited; end; end.