Move handles equally either side of a node

Is there a way of dragging a handle to an equal distance either side of a node like in FontLab? I think it was shift or option drag to activate both handles while dragging one. This would be handy for symmetrical glyphs like O.

It works by holding ctrl-opt while dragging or moving a handle with the arrow keys.

Thanks. I tried all sorts of combos but couldn’t figure it out.