Allow both types of constrained drag (again).

	- Holding the constraint modifier at the time of grab gives constrained x.

	- Holding the constraint modifier after the grab but before the first motion
	  constrains to the direction of first movement.

1 files changed, 10 insertions, 1 deletions

diff --git a/gtk2_ardour/editor_drag.cc b/gtk2_ardour/editor_drag.cc
index 98ccf4a6a2..07f6c23d71 100644
--- a/gtk2_ardour/editor_drag.cc
+++ b/gtk2_ardour/editor_drag.cc
@@ -264,6 +264,15 @@ Drag::start_grab (GdkEvent* event, Gdk::Cursor *cursor)
 	/* we set up x/y dragging constraints on first move */
 	_constraint_pressed = ArdourKeyboard::indicates_constraint (event->button.state);
 
+	if (_constraint_pressed) {
+		/* if constraint was indicated at the beginning of the drag, constrain x.
+		   if the user presses these modifiers after this point in time (first move),
+		   the drag will be constrained to the first direction of motion.
+		*/
+		_x_constrained = true;
+		_y_constrained = false;
+	}
+
 	_raw_grab_frame = _editor->canvas_event_sample (event, &_grab_x, &_grab_y);
 
 	setup_pointer_frame_offset ();
@@ -429,7 +438,7 @@ Drag::motion_handler (GdkEvent* event, bool from_autoscroll)
 							_x_constrained = true;
 							_y_constrained = false;
 						}
-					} else if (_constraint_pressed) {
+					} else if (!_constraint_pressed && ArdourKeyboard::indicates_constraint (event->button.state)) {
 						// if dragging normally, the motion is constrained to the first direction of movement.
 						if (_initially_vertical) {
 							_x_constrained = true;