procedure TfmMain.lbClientsDrawItem(Control: TWinControl; Index: Integer; Rect: TRect; State: TOwnerDrawState);
const
  PBarHeight: Integer = 10;
  PBarWidth: Integer = 60;
var
  ListBox: TListBox absolute Control;
  TopMargin: Integer;
begin
  with ListBox.Canvas do
  begin
    ...
    FillRect(Rect);
    ...
    Pen.Color := Font.Color;
    Brush.Style := bsClear;
    TopMargin := (Rect.Height - PBarHeight) div 2;
    Rectangle(Rect.Right - PBarWidth - 4, Rect.Top + TopMargin, Rect.Right - 4, Rect.Top + PBarHeight + TopMargin);
//    Pen.Style := psClear;
  end;
end;