[orca-list] On Thunderbird: Orca doesn't read the first line when moving with page up

[Alex ARNAUD <alexarnaud hypra fr>]

Hello all

Environment:
- Debian SId
- Orca master
- Thunderbird 52

Steps to reproduce:
1) Open Thunderbird
2) Write a new message (here in plein text)
3) Write two or three lines
4) Press page up

Result: The cursor goes on the first line but Orca stays silent so the 
user cannot know it has moved

Expected result: Orca should read the line where the focus goes

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