vwindow->gui->lock_window("VTracking::update_tracker");
vwindow->get_edl()->local_session->set_selectionstart(position);
vwindow->get_edl()->local_session->set_selectionend(position);
vwindow->gui->lock_window("VTracking::update_tracker");
vwindow->get_edl()->local_session->set_selectionstart(position);
vwindow->get_edl()->local_session->set_selectionend(position);