Оформил: DeeCo
Автор: http://www.swissdelphicenter.ch

private
   procedure WMNCRBUTTONDOWN(var msg: TMessage); message WM_NCRBUTTONDOWN;
   procedure WMNCLBUTTONDOWN(var msg: TMessage); message WM_NCLBUTTONDOWN;
   procedure WMNCLBUTTONDBLCLK(var msg: TMessage); message WM_NCLBUTTONDBLCLK;
 end;



 implementation


 procedure TForm1.WMNCRBUTTONDOWN(var msg: TMessage);
 begin
   if msg.wParam = HTCAPTION then Caption := 'Right Click!';
   // Message.Result := 0; {to ignore the message} 
  inherited;
 end;

 procedure TForm1.WMNCLBUTTONDOWN(var msg: TMessage);
 begin
   if msg.wParam = HTCAPTION then Caption := 'Left Click!';
   // Message.Result := 0; {to ignore the message} 
  inherited;
 end;

 procedure TForm1.WMNCLBUTTONDBLCLK(var msg: TMessage);
 begin
   if msg.wParam = HTCAPTION then Caption := 'Double Click!';
   // Message.Result := 0; {to ignore the message} 
  inherited;
 end;