diff --git a/gtk2_ardour/monitor_section.cc b/gtk2_ardour/monitor_section.cc
index bdc8868738..e618b3a7a0 100644
--- a/gtk2_ardour/monitor_section.cc
+++ b/gtk2_ardour/monitor_section.cc
@@ -436,7 +436,7 @@ MonitorSection::MonitorSection ()
 	vpacker.pack_start (master_packer,        false, false, PX_SCALE(10));
 	vpacker.pack_end   (*out_packer,          false, false,
 #ifdef MIXBUS
-			scrollbar_height - 2 /* no outer frame */
+			scrollbar_height /* no outer frame */
 #else
 			scrollbar_height + 2 /* frame borders */
 #endif