/** @return index of this TimeAxisView within its parent */
int order () const { return _order; }
/** @return maximum allowable value of order */
static int max_order () { return _max_order; }
/** @return index of this TimeAxisView within its parent */
int order () const { return _order; }
/** @return maximum allowable value of order */
static int max_order () { return _max_order; }