clip recording: begin/end write only happens on trigger arm/disarm

gtk2_ardour/midi_cue_editor.cc

@@ -496,11 +496,6 @@ MidiCueEditor::idle_data_captured ()
 void
 MidiCueEditor::box_rec_enable_change (ARDOUR::TriggerBox const & b)
 {
-	if (b.record_enabled()) {
-		view->begin_write();
-	} else {
-		view->end_write ();
-	}
 }
 
 void

gtk2_ardour/midi_view.cc

@@ -1573,6 +1573,8 @@ MidiView::begin_write()
 	   XXX this should not happen.
 	*/
 
+	clear_events ();
+
 	if (_active_notes) {
 		for (unsigned i = 0; i < 128; ++i) {
 			delete _active_notes[i];

libs/ardour/triggerbox.cc

@@ -292,6 +292,12 @@ Trigger::request_trigger_delete (Trigger* t)
 void
 Trigger::arm ()
 {
+	if (_box.record_enabled() == Recording) {
+		return;
+	}
+
+	std::cerr << "try to arm " << _box.order() << ':' << index() << std::endl;
+
 	/* trigger arming is mutually exclusive within a given TriggerBox */
 
 	_box.disarm_all ();
@@ -308,7 +314,7 @@ Trigger::arm ()
 	_box.arm_from_another_thread (*this, _box.session().transport_sample(), chns);
 	_armed = true;
 	ArmChanged(); /* EMIT SIGNAL */
-	TriggerArmChanged (this);
+	TriggerArmChanged (this); /* EMIT SIGNAL */
 }
 
 void
@@ -3609,7 +3615,8 @@ TriggerBox::finish_recording (BufferSet& bufs)
 	*/
 	ai->slot.captured (*ai, bufs);
 	_arm_info = nullptr;
-	_record_state = Disabled;
+	std::cerr << "finish, ai null\n";
+	_record_state = Enabled;
 }
 
 void