Message problem

[EWeiss]

warum komme ich nicht in diese Message ?
LBUTTONDOWN !

Delphi-Quellcode:

function VisualProc(WndHandle : HWND;
                    Msg : DWORD; wParam, lParam : Longint): longInt; stdcall;
var
  ps : PAINTSTRUCT;

begin

    if Msg = WM_ERASEBKGND then
      begin
        Result := 1;
        exit;
      end else
      if Msg = WM_MOUSEMOVE then
      begin
        if (Msg = WM_LBUTTONDOWN) then
          if (GetFocus <> WndHandle) then
            SetFocus(WndHandle);

        BassBoxInfo^.Msg    := BBP_MOUSE;
        BassBoxInfo^.WinMsg := Msg ;
        BassBoxInfo^.wParam := wParam;
        BassBoxInfo^.lParam := lParam;

        BbpPluginFunc(BassBoxInfo^);
      end else

      if Msg = WM_PAINT then
      begin
        BeginPaint(WndHandle, ps);
        EndPaint(WndHandle, ps);
        Result := 0;
        Exit;
      end;
    result := DefWindowProc(WndHandle, Msg, wParam, lParam);

end;

hinter WM_LBUTTONDOWN komme ich bei WM_MOUSEMOVE hinein
Fokus ist auch vorhanden.

gruss Emil