diff --git a/gtk2_ardour/ui/master_ui.xml b/gtk2_ardour/ui/master_ui.xml
index 3e1293afc9..93add5359f 100644
--- a/gtk2_ardour/ui/master_ui.xml
+++ b/gtk2_ardour/ui/master_ui.xml
@@ -68,4 +68,8 @@
               activeicon="master_global_rec_active"
               prelighticon="master_global_rec_prelight"
               ui.orphan="true"/>
+  <icon id="master_bus_multi_out_mode_icon"
+        source="master_bus_multi_out_mode.png"
+        ui.orphan="true"/>
+
 </RouteUI>