speeding up the hint display

In a listbox, I wanted to code a hint on mousemove.

I coded this :

procedure TFMagicWinner.ListBox2MouseMove(Sender: TObject;
  Shift: TShiftState; X, Y: Integer);
var
  p : TPoint;
  itemnum : integer;
begin
  p.x := x;
  p.y := y;
  itemnum := listbox2.Itematpos(p, true);
  if itemnum > -1 then
  begin
      ListBox2.showhint := false;
      listbox2oldpos := itemnum;
      ListBox2.hint := ListBox2.Items[ItemNum];
      ListBox2.showhint := true;
  end;
end;
it works fine when I enter on the control, but when I move the mouse over it, the hint is not redisplayed.
The problem does not come from the mousemove event which is triggered correctly but from the fact that I cannot display the hint when I want.

I am sure somebody has a simple solution for that