[orca-list] Orca doesn't keep web page position when switching between workspace and window

[Alex ARNAUD <alexarnaud hypra fr>]

Hello,

Environment:
* Debian 9 "Stretch"
* Orca master
* Mate 1.16 (GTK3)
* Firefox 68 with e10s enabled
* Thunderbird daily
* Window manager: Compiz
* Opened window for testing:
- Workspace1: Firefox
- Workspace3: Thunderbird

Steps to reproduce:
1) Open this page: 
https://openclassrooms.com/fr/courses/761582-maitrisez-la-2d-avec-photoshop/760063-limagerie-numerique-pour-les-zeros

2) Go on the line "couleur unique"

3) Switch to the workspace 3 (here with windows + 3)

4) Switch to the workspace 1 ((here with windows + 1) and then press 
quickly down arrow  (I don't wait Orca feedback because I know exactly 
where I am and I know I'd like to continue to read)

Result with Orca enabled:
The caret switch back to the top of the page.

Result with Orca disabled and caret navigation enabled:
The caret stays at its position and pressing down arrow move on the next 
line.

Best regards,
Alex.