@Override
        public boolean onGesture(final Gesture g, final MotionEvent e) {
            if (g instanceof Gesture.Tap) {
                final GeoPoint p = mMap.viewport().fromScreenPoint(e.getX(), e.getY());
                onTapCallback(p.latitudeE6, p.longitudeE6, (int) e.getX(), (int) e.getY(), false);
                return true;
            } else if (g instanceof Gesture.LongPress) {
                final GeoPoint p = mMap.viewport().fromScreenPoint(e.getX(), e.getY());
                onTapCallback(p.latitudeE6, p.longitudeE6, (int) e.getX(), (int) e.getY(), true);
                return true;
            }
            return false;
        }
call this instead of VTM.layers().add so that we can keep track of layers added by the tile provider
main/src/main/java/cgeo/geocaching/unifiedmap/mapsforgevtm/MapsforgeVtmFragment.java