... 
  public 
    procedure WMNCRButton(var Msg: TWMNCHitMessage); message WM_NCRButtonDown; 
    procedure WMSysCommand(var Msg: TWMSysCommand); message WM_SYSCOMMAND; 
  end; 
 
var 
  Form1: TForm1; 
 
implementation 
 
{$R *.dfm} 
 
procedure TForm1.WMSysCommand(var Msg: TWMSysCommand); 
begin 
  if (Msg.CmdType = SC_KEYMENU) or (Msg.CmdType = SC_MOUSEMENU) 
    or (Msg.CmdType = 61587) 
    then Msg.Result := 0 
  else inherited; 
end; 
 
procedure TForm1.WMNCRButton(var Msg: TWMNCHitMessage); 
begin 
  Msg.Result := 0; 
end;