Solve https://phabricator.wikimedia.org/T19496

After saving preferences, a message is displayed that says "Your preferences have been saved.". But if I keep doing changes to my preferences, and I leave my computer, then when I come back in front of my screen, I don't remember whether or not my changes have been saved. Some JavaScript code could automatically hide this message when changing preferences.

You can take hints from the previous patches which worked but now are outdated.

Submit a patch to Gerrit and get it positively reviewed to solve the task.