From dd05f1e257f8a715d23625bb725a727c57c4c0b6 Mon Sep 17 00:00:00 2001
From: Tim Mayberry <mojofunk@gmail.com>
Date: Wed, 3 Feb 2016 22:23:55 +1000
Subject: [PATCH] Fix bug #5633, Don't drop all midi bindings when a track is
 removed

Only drop the controllable that is being destroyed, not all of them.
---
 libs/surfaces/generic_midi/midicontrollable.cc | 8 +++++---
 libs/surfaces/generic_midi/midicontrollable.h  | 2 +-
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/libs/surfaces/generic_midi/midicontrollable.cc b/libs/surfaces/generic_midi/midicontrollable.cc
index 3a1aea592f..1051503fc4 100644
--- a/libs/surfaces/generic_midi/midicontrollable.cc
+++ b/libs/surfaces/generic_midi/midicontrollable.cc
@@ -142,7 +142,7 @@ MIDIControllable::set_controllable (Controllable* c)
 
 	if (controllable) {
 		controllable->Destroyed.connect (controllable_death_connection, MISSING_INVALIDATOR,
-						 boost::bind (&MIDIControllable::drop_controllable, this),
+						 boost::bind (&MIDIControllable::drop_controllable, this, _1),
 						 MidiControlUI::instance());
 	}
 }
@@ -264,9 +264,11 @@ MIDIControllable::lookup_controllable()
 }
 
 void
-MIDIControllable::drop_controllable ()
+MIDIControllable::drop_controllable (Controllable* c)
 {
-	set_controllable (0);
+	if (c == controllable) {
+		set_controllable (0);
+	}
 }
 
 void
diff --git a/libs/surfaces/generic_midi/midicontrollable.h b/libs/surfaces/generic_midi/midicontrollable.h
index a19e3a1a28..8c14856742 100644
--- a/libs/surfaces/generic_midi/midicontrollable.h
+++ b/libs/surfaces/generic_midi/midicontrollable.h
@@ -142,7 +142,7 @@ class MIDIControllable : public PBD::Stateful
 	std::string     _what;
 	bool            _bank_relative;
 
-        void drop_controllable();
+  void drop_controllable (PBD::Controllable*);
 
 	void midi_receiver (MIDI::Parser &p, MIDI::byte *, size_t);
 	void midi_sense_note (MIDI::Parser &, MIDI::EventTwoBytes *, bool is_on);