diff --git a/gtk2_ardour/automation_line.cc b/gtk2_ardour/automation_line.cc
index b435ead368..a469888119 100644
--- a/gtk2_ardour/automation_line.cc
+++ b/gtk2_ardour/automation_line.cc
@@ -539,8 +539,13 @@ AutomationLine::ContiguousControlPoints::clamp_dx (double dx)
 	}
 
 	tx = cp->get_x() + dx; // new possible position if we just add the motion
+
+	tx = max (tx, 0.);
+	tx = min (tx, region_limit);
+
 	tx = max (tx, before_x); // can't move later than following point
 	tx = min (tx, after_x);  // can't move earlier than preceding point
+
 	return  tx - cp->get_x ();
 }
 
@@ -637,8 +642,10 @@ AutomationLine::drag_motion (double const x, float fraction, bool ignore_x, bool
 	 */
 
 	if (dx < 0 || ((dx > 0) && !with_push)) {
-		for (vector<CCP>::iterator ccp = contiguous_points.begin(); ccp != contiguous_points.end(); ++ccp) {
-			dx = (*ccp)->clamp_dx (dx);
+		const timepos_t rl (maximum_time() + _offset);
+		double region_limit = trackview.editor().duration_to_pixels_unrounded (timecnt_t (rl, get_origin()));
+		for (auto const & ccp : contiguous_points){
+			dx = ccp->clamp_dx (dx, region_limit);
 		}
 	}
 
diff --git a/gtk2_ardour/automation_line.h b/gtk2_ardour/automation_line.h
index fac5ce5562..492dd1a954 100644
--- a/gtk2_ardour/automation_line.h
+++ b/gtk2_ardour/automation_line.h
@@ -194,7 +194,7 @@ protected:
 	class ContiguousControlPoints : public std::list<ControlPoint*> {
 public:
 		ContiguousControlPoints (AutomationLine& al);
-		double clamp_dx (double dx);
+		double clamp_dx (double dx, double region_limit);
 		void move (double dx, double dvalue);
 		void compute_x_bounds (PublicEditor& e);
 private:
diff --git a/gtk2_ardour/editor_drag.cc b/gtk2_ardour/editor_drag.cc
index 7b11aaa219..e823f9e69a 100644
--- a/gtk2_ardour/editor_drag.cc
+++ b/gtk2_ardour/editor_drag.cc
@@ -4775,6 +4775,7 @@ ControlPointDrag::motion (GdkEvent* event, bool first_motion)
 		cy = zero_gain_y;
 	}
 
+	/* cx_pos is in absolute timeline units */
 	timepos_t cx_pos (timepos_t (pixel_to_time (cx)) + snap_delta (event->button.state));
 
 	if (need_snap) {
@@ -4782,7 +4783,9 @@ ControlPointDrag::motion (GdkEvent* event, bool first_motion)
 	}
 
 	cx_pos.shift_earlier (snap_delta (event->button.state));
-	cx_pos = min (cx_pos, _point->line().maximum_time() + _point->line().offset());
+
+	/* total number of pixels (canvas window units) to move */
+	double px = _editor->time_to_pixel_unrounded (cx_pos);
 
 	float const fraction = 1.0 - (cy / _point->line().height());
 
@@ -4791,8 +4794,9 @@ ControlPointDrag::motion (GdkEvent* event, bool first_motion)
 		_editor->begin_reversible_command (_("automation event move"));
 		_point->line().start_drag_single (_point, _fixed_grab_x, initial_fraction);
 	}
+
 	pair<float, float> result;
-	result = _point->line().drag_motion (_editor->time_to_pixel_unrounded (cx_pos), fraction, false, _pushing, _final_index);
+	result = _point->line().drag_motion (px, fraction, false, _pushing, _final_index);
 	show_verbose_cursor_text (_point->line().get_verbose_cursor_relative_string (result.first, result.second));
 }