[orca-list] When clicking with left click on the web Orca clicks on another link

[Alex ARNAUD <aarnaud hypra fr>]

Hello,

Tested environment:
* Debian 8 and 9
* Orca 3.24 and master
* Firefox ESR 60 and Nightly

This issue has been reported to me by a blind user.

Steps to reproduce:
1) Open www.google.com
2) Choose the link to display all Google applications
3) Tab until choosing Google Drive
Note: Pressing enter doesn't work and close the application menu so it's 
not possible to do that
4) Do a left click with the Orca function

Result:
Orca clicks on "About account" (translate from French)

Expected result:
Orca should click on Google Drive link

Best regards,
Alex.