procedure TForm1.ComboBox1DrawItem(Control: TWinControl; Index: Integer; Rect: TRect; State: TOwnerDrawState);
begin
with (Control as TComboBox) do
begin
Canvas.FillRect(Rect);
SetTextAlign(Canvas.Handle, TA_RIGHT);
Canvas.TextOut(Rect.Right - 4, Rect.Top, Items[Index]);
end;
end;