Background apps cannot be navigated by keyboard
The menu's items are non-reactive because they cannot be activated. As a result, keynav gets stuck when it hits any item:
- open quick settings
- click background apps
- press down arrow
- no more keynav with either arrow keys or tab
When making the menu items reactive-but-non-activatable, keynav doesn't get stuck. But it doesn't allow navigating to the close buttons, which are the elements that actually do something, so that's not really a fix (or at least not a complete one).