Bug: Stuck in a focus loop trying to focus outside day

[DanielJKelly]

Bug description

This bug is related to focusing and outside days. It seems to occur in "range" mode when showing multiple months and the day that will be initially focused is part of the selected range and present on one calendar and also on the other calendar as an outside day. Both the "inside" day and the outside day have tabIndex="0" when inspected.

My initial thought is that outside days should not be considered focusable (or maybe at least have it be an option?), but perhaps I am missing a valid use case.

So perhaps this line should be checking for !activeModifiers.outside as well? I haven't tried it out myself though, so it's possible the issue is due to something else.

To reproduce

Fork this CodeSandbox: https://codesandbox.io/s/react-day-picker-8-vl4ry with the code to reproduce the issue.

Steps

1. Focus the date picker
2. Press Tab until a day on the calendar is focused
3. Keep pressing Tab and you will be stuck cycling back between the day being focused and the right arrow being focused. You can sometimes see focus indicator on the outside day flash before focus is shifted to the "inside" day.

Expected behavior

I would expect that the focus should continue on to the next tabbable element and that the button shown below the DayPicker can be focused.

Screenshots

rdp-ex-bug.mov

Additional context

Add any other context about the problem here.