[orca-list] Regression: Orca says "no focus" on Thunderbird when opening a mail

[Alex ARNAUD <alexarnaud hypra fr>]

Hello all,

Environment:
- Debian Stretch with an upgraded a11y stack
- Orca master
- Thunderbird 52.9.1, mail are opened in a separate window in my 
Thunderbird configuration

This issue is not easy to reproduce, what I've seen is when you're 
opening a mail sometime Orca says "no focus". I don't understand why 
Orca says that right now, in 3.28 this issue doesn't happen.

Steps I've done with a mail I've encounter the issue:
1) Open the mail, move the caret at the top of the mail
2) Directly close the mail with ctrl+w
3) Open the mail with the return key

I've generated a debug out: 
https://framabin.org/p/?4398c7b95cf25769#ClvXDHLQxjn24Q2cGVsATptkBdcc5D71jTmmg6IlNbQ=

Best regards.
--
Alex ARNAUD
Visual-Impairment Project Manager
Hypra - "Humanizing technology"