Panels are inaccessible for Orca screen reader

[pavelvlcek]

Steps to reproduce.

1. Launch Orca screen reader.
2. Activate one of the panels, for example alt lus f1 or ctrl plus alt plus up / down
3. Orca says "panel", navigation in panels is impossible for blind users now.

[xenopeek]

Related issues for sight-impaired users: #5592, #5593 and #4715

[icarter09]

@pavelvlcek

[Vahan86]

@icarter09, can we close this issue?