diff --git a/gtk2_ardour/editor_rulers.cc b/gtk2_ardour/editor_rulers.cc
index 1156c28cf6..6334b72ce7 100644
--- a/gtk2_ardour/editor_rulers.cc
+++ b/gtk2_ardour/editor_rulers.cc
@@ -89,6 +89,7 @@ Editor::initialize_rulers ()
 
 	visible_timebars = 1; /*this will be changed below */
 	ruler_pressed_button = 0;
+	canvas_timebars_vsize = 0;
 }
 
 bool