diff --git a/gtk2_ardour/editor_drag.cc b/gtk2_ardour/editor_drag.cc
index 23f6ef1b30..999df950dd 100644
--- a/gtk2_ardour/editor_drag.cc
+++ b/gtk2_ardour/editor_drag.cc
@@ -4118,6 +4118,9 @@ CursorDrag::start_grab (GdkEvent* event, Gdk::Cursor* c)
 
 	fake_locate (where.sample - snap_delta (event->button.state));
 
+	_last_mx = event->button.x;
+	_last_my = event->button.y;
+	_last_dx = 0;
 	_last_y_delta = 0;
 }