I recently upgraded to Mavericks (download from app store).

Before this upgrade, I could click on the the notifications UI element at the very top-right of the display; this would cause the whole screen to shift to the left and display a list of notifications:

Now, after the upgrade, this UI element simply turns blue during the mousedown, and nothing else happens.

Are there any known fixes or workarounds to this?

I recently upgraded to Mavericks (download from app store).

Before this upgrade, I could click on the the notifications UI element at the very top-right of the display; this would cause the whole screen to shift to the left and display a list of notifications:

Now, after the upgrade, this UI element simply turns blue during the mousedown, and nothing else happens.

Are there any known fixes or workarounds to this?

I should add I am experiencing a similar but not identical issue with the spotlight UI element:

When I click on this one, I just get a "bonk" sound and no spotlight search bar. However I can use spotlight without problems from finder windows, etc.

I don't know, but I'm guessing these two issues may be related simply because of their proximity on the screen.

Other taskbar UI elements appear to be working normally.