Clicking on current full date or "Add event" does nothing

I click on the date&time widget. A dropdown appears.

The topmost row contains today's full date, e.g. "Wednesday, 16 October 2013". On mouseover it is highlighted, and on clicking it disappears. Hence I assume it's a menu entry intended to do something. There's also an "Add event...".

Neither of these two do anything for me. Not even an error message. They should at least give me a popup telling which packages I need to install for these two to work.

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: indicator-datetime 13.10.0+13.10.20131011-0ubuntu1
ProcVersionSignature: Ubuntu 3.11.0-12.19-generic 3.11.3
Uname: Linux 3.11.0-12-generic x86_64
ApportVersion: 2.12.5-0ubuntu2
Architecture: amd64
Date: Wed Oct 16 00:08:10 2013
InstallationDate: Installed on 2012-05-30 (503 days ago)
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
MarkForUpload: True
SourcePackage: indicator-datetime
UpgradeStatus: Upgraded to saucy on 2013-10-12 (2 days ago)