Calendar, notification button no longer work

The calendar that usually pops up when you click on the date in the tasktray doesn't work, and the clicking bell doesn't show the notification area. The taskbar is at the bottom of the screen.

According to Start 11v2, my software is up to date, and the "About" page in Settings says version 2.11.

If downgrading to 2.10 (or whatever the last version was) will get my calendar back, can I do that?

Thanks.