This would make it much easier to skim the mouse over all of the grids or flex box containers on a page to quickly activate the overlay for the one I want, instead of carefully hovering over the appearing/disappearing "Jump to" arrow to make sure I'm enabling the container I want. This would be very helpful on pages where many elements have the same or similar CSS selectors.
<rdar://problem/91997969>
*** This bug has been marked as a duplicate of bug 239621 ***