Hi Tsiao, just to help clarify:

> The symmetry works using the little yellow corner, but it moves
> only horizontally, it just does not move freely..
> I am probably not doing something right..

Yeah you can't move a point diagonally just in one single motion using this method, but you can move it either horizontally using the corner grips or vertically by just dragging on the points and going up and down (you want to have "Straight snap" enabled to get vertical snaps engaged). So in order to do a diagonal mirrored move you do it in 2 steps - move a horizontal step with the corner grip and then a vertical move by dragging on the point itself.

In the future I do want to add more ways to control symmetry, but right now that method is the easiest way.

One thing to note with the edit frame corner grips is that if you just click and release on a corner grip instead of holding down and dragging on it, it will change the scale origin from "scale from center" mode into the alternate "scale from opposite corner" mode, so if you see the scale behavior change to scaling with the anchor being the opposite corner it means that you clicked one time on the grip instead of dragged on it and so you need to click on it again to flip the mode around again.

When you move your mouse over a scaling corner grip a marker will appear either at the center or at the opposite corner to show you the current anchor mode.

- Michael