+ SCM count = get_property ("tempoUnitCount");
+ SCM duration = get_property ("tempoUnitDuration");
+ SCM text = get_property ("tempoText");
+
+ if ( ( (unsmob_duration (duration) && scm_is_number (count))
+ || Text_interface::is_markup (text) )
+ && !(ly_is_equal (count, last_count_)
+ && ly_is_equal (duration, last_duration_)
+ && ly_is_equal (text, last_text_)))