We used to have this functionality with Evolution: clicking on the date-time in the gnome panel would show a list of events/tasks/appointments from the Evolution Calendar. As an interesting side effect, one would receive alarm notifications even when Evolution wasn't running.
Now that Thunderbird is the default email client, I'd imagine that there is a similar functionality for Lightning (Thunberbird's calendar). I just can't find it. Maybe it's not ready ?
There's the Thunderbird Addon (Evolution Sync) that should help you with this. It's pretty awesome if you have a simple setup in Thunderbird. (https://addons.mozilla.org/en-us/thunderbird/addon/evolution-mirror/)
I ended up stopping to use this since I had some remote calendars (iCals) from other sites and each time it checked those it would then add another entry to the Evolution calendar. I tried to email the actual maintainer but I got no love. So I went back to the old way of doing that.
Like I said though it's pretty slick in general :)
Good luck!
Add your Google Calendar to your Evolution.
Evolution is now two-way sync ready with Google Calendar out of the box, so you shouldn’t have any trouble adding a new calendar there.
Once you’ve done that, if your Lightning is also linked to the same calendar, whatever changes you make in Thunderbird/Lightning will be reflected in your date/time applet.
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