diff --git a/gtk2_ardour/mixer_ui.cc b/gtk2_ardour/mixer_ui.cc
index 129ad39aa5..6e64ff4f4a 100644
--- a/gtk2_ardour/mixer_ui.cc
+++ b/gtk2_ardour/mixer_ui.cc
@@ -2639,7 +2639,6 @@ Mixer_UI::monitor_section_going_away ()
 
 	monitor_section_detached ();
 	out_packer.remove (_monitor_section.tearoff());
-	_monitor_section.set_session (0);
 }
 
 void