Calendar/ reminder wanted - recommendations

[AG <computing.account@googlemail.com>]

I used to use korganizer, but for whatever reason it no longer minimises 
to my notification area in Gnome, and when it does I cannot click it to 
open it to add new reminders.

I want to have a reminder that can run in the background when I don't 
need it and minimises to the notification area (system tray?) in Gnome 
(the area near the clock on a default lay out), and when an appointment 
is due it pops up with a reminder.  There are any number of calendars, 
etc., but I haven't been able to find something that I am looking for 
(such as something similar to korganizer).

Can anyone make a recommendation please?  I am running Testing.

Thanks.

AG