Preconditions: Enable realtime collaboration for the WYSIWYG editor

• As Admin click on Drawer > Administer Wiki > Editing > WYSIWYG Editor
• Remove (uncheck) the "xwiki-realtime" from the list of disabled plugins in the CKEditor administration section
• Click on the Save button

Steps to reproduce:

1. As a simple user (user01) edit any page
2. Open a new private (incognito) browser window and login with another simple user (user02)
3. Access the same page and edit it, forcing the lock
4. Add some text
5. Switch to the window of the first user (user01) and add some text on the same line

Expected results: All the users avatars that are editing the same line appear at the beginning of the row.

Actual results: Only the avatar of the first user that edited that line appears at the beginning of the row.