Expected VO gesture behavior for combobox or listbox interactions

Hi ARIA folks,
I’m struggling with the best VO gesture solution for a popped-up listbox interaction.

We have the interaction working nicely with VO and keyboard on MacOS; however, on iOS the listbox can stay open if the cursor is moved out of the box without making a new selection or dismissing the box.

Basically, if the box is open and the user flicks up or down the cursor will move out of the box into the surrounding content, but focus is not entirely lost, so the box stays open.

My questions are:
Should users have access to the surrounding content when a listbox or combobox is open?
If yes, is there a better way to handle the closing of the box besides listening for loss of focus?
If no, what’s the best way to handle these popped-up list interactions? Is it best to treat them more like an opened dialog and restrict focus to the popped up list until the interaction is dismissed or a new section is made?

To try out what we have implemented please try this link in Safari on iOS with VO turned on. The app is a interactive science simulation about concentration. It’s called Molarity. It has interactive description and sonification.

https://phet-dev.colorado.edu/html/molarity/1.6.0-dev.2/phet/molarity_en_phet.html?a11y&supportsSound <https://phet-dev.colorado.edu/html/molarity/1.6.0-dev.2/phet/molarity_en_phet.html?a11y&supportsSound>

Taliesin
~.~.~
Also available off list at:
Taliesin.Smith@colorado.edu
Inclusive Design Researcher
PhET Interactive Simulations
https://phet.colorado.edu/en/accessibility
Physics Department
University of Colorado, Boulder