OnMousewheel event problem

det er en generel fejl i dbgrid men det her skulle løse problemet:

public
    procedure AppMessage(var Msg: TMsg; var Handled: Boolean);


procedure TOversigt.AppMessage(var Msg: TMsg; var Handled: Boolean);
var
  i: SmallInt;
begin
  {Mouse wheel behaves strangely with DbGrids - this proc sorts this out}
  if Msg.message = WM_MOUSEWHEEL then
  begin
    Msg.message := WM_KEYDOWN;
    Msg.lParam := 0;
    i := HiWord(Msg.wParam);
    if i > 0 then
      Msg.wParam := VK_UP
    else
      Msg.wParam := VK_DOWN;

    Handled := False;
  end;
end;

procedure TOversigt.FormCreate(Sender: TObject);
begin
Application.OnMessage := Oversigt.AppMessage;  //scroll mouse scroll to bottom of list
end;

Virker perfekt !! tak for hjælpen.