diff --git a/libs/surfaces/generic_midi/midicontrollable.cc b/libs/surfaces/generic_midi/midicontrollable.cc
index 6afd9d4d8a..bed85f49b4 100644
--- a/libs/surfaces/generic_midi/midicontrollable.cc
+++ b/libs/surfaces/generic_midi/midicontrollable.cc
@@ -88,6 +88,8 @@ MIDIControllable::MIDIControllable (GenericMidiControlProtocol* s, MIDI::Parser&
 MIDIControllable::~MIDIControllable ()
 {
 	drop_external_control ();
+	delete _descriptor;
+	_descriptor = 0;
 }
 
 int