Focus Order, Accessibility, and Set Focus

Crap, I wrote back yesterday but apparently it didn't save my reply.

Let me try again.

In theory you are right about the yellow square not appearing over non interactive elements. For me, it appears on the previous interactive object you selected.

I also found that NVDA automatically reads elements in the focus order if they start at 0:00 on the timeline.

So, here's an example:
Base slide has 4 popup buttons, each revealing a layer that has a title, text, and a close button.

Case 1:
No Set Focus enabled on the titles in the popup
"Prevent users from clicking on other layers" is enabled.

Selecting the popup opens the layer
Pressing down results in either a blank or you're kicked out of the slide and you need to find your way back to "Back to top" which can be annoying.

Case 2:
Set Focus enabled on the titles in the popup
"Prevent users from clicking on other layers" is enabled.

Selecting the popup opens the layer.
A yellow square appears on the button that you clicked on to open the popup
Yellow square disappears once the set focus on Title when Title Starts kicks in
Pressing down is fine.

Case 3:
No Set Focus enabled on the titles in the popup
"Prevent users from clicking on other layers" is disabled

Selecting the popup opens the layer
Pressing down works
However....if you use back to top, you have to cycle back through all the base layer elements, which can be really annoying on slides where you're 6 layers in.

I guess out of the 3.....Case 3 is best? I just don't know how often someone who uses keyboard nav would click "back to top" and get infuriated that they have to travel back to wherever they were