public void mousemove(Coord c) {
        if (locked)
            return;
        if ((!locked) && (dragging == null) && (pressed != null)) {
            dragging = pressed;
            int slot = index(c);
            if (slot >= 0) {
                clearslot(slot);
            }
            pressed = null;
        } else {
            super.mousemove(c);
        }

    }