With the recent update to auto-layout, the horizontal resizing (fit/fill/fixed) is now relegated to a dropdown, introducing a new click. At the same time the alt-double-click shortcut was introduced, but from what I can tell, only works in one direction: → Fill. Alt-double-clicking a filled element will not return it to fixed or fit. I’ve also found that the shortcut doesn’t work on paths, where double-clicking enters path edit mode or whatever. So if you want to drop in a line and double-click to fill its parent as a divider, you need to use the dropdown.
Am I missing something with this shortcut?