The reason for this is that the clock applet width is not enough to show tasks
and appointments of even a small size in the subject, because of this, sometimes
you can't grasp the idea of the task/appointment by just viewing the clock
applet in the task bar.

If you look carefuly at it, the tasks and appoinments are list items that you
can select with a single click.  That way, I think it is very simple (I might be
wrong) to add a tooltip text that shows clearly the whole subject of the hovered
task/appointment.

I think this new feature should be considered for inclusion in the stable branch
as well as in the HEAD branch.

PS.  Why the clock-applet isn't as a component in bugzilla?