Could be caused by T139114: Marking notification as read causes "TypeError: sourceModel is null"

Do you get a JS error in the console just before it navigates away?

In betalabs the clickable area for 'Mark as read' blue dot seems to be sufficient enough. Clicking directly on the blue dot marks the msg as read (Chrome 50).

There is another bug found when I was looking into this issue - T139381: [minor] When cross-wiki notifications mark as read - the flyout does not display anything; it's relatively minor since it happens when only cross-wiki notifications are present (and no locals).

Change 298814 had a related patch set uploaded (by Mooeypoo):
Prevent click propogation when clicking 'mark as read' button

https://gerrit.wikimedia.org/r/298814

This is a tentative fix; according to what I saw on @Etonkovidova computer when debugging this, it seems that the proper method is called (responding to 'onMarkAsReadButtonClick') but the link is still clicked. I think this happens because the mark-as-read button is inside the content, and the content is surrounded by a <a> link, so the button responds, but then the click is propogated.

This commit should stop the propogation by returning false on that action, but I could not reproduce this bug directly in master, so I can't verify that this stops all occurrences. In any case it seems like a good thing to have in general in that case.

Presently, the bug exists in 1.28.0-wmf.8 (rMWf9d38787d2e7) displaying (very briefly)

Uncaught TypeError: Cannot read property 'findByIds' of null

1.28.0-alpha (090b37a) (betalabs) does not show the bug.

Change 298814 merged by jenkins-bot:
Prevent click propogation when clicking 'mark as read' button

https://gerrit.wikimedia.org/r/298814

Checked in betalabs - works as expected. Marked this issue as one of the priority items to be checked in production after deploy.