A great idea but let down by poor implementation. Rated 2 out of 5 stars

Year View is unbelievably slow and has always has been for some reason? When you click on the Year View tab it will take forever to load up all your calendar entries resulting in you unable to use Thunderbird until it completes. You sit there being mesmerised by the little spinning wheel! Why this happens is a mystery which 'fabrix' has never been able to fix.

The logical option is to disable the loading up of calendar entries and just use it as a quick way to look up future dates. It's nice to have a year view; but the UI is so crowded when it loads up entries it's not really much use anyway. Having an option to disable some or all of your calendar entries would be a great addition. As it is, it's unusable and I've had to disable it.

I will try and use it again in the future and see if it's fixed or a disable calendar entries option has been implemented, because, as I said, it's a good idea, and I appreciate the effort, but I won't hold my breath.

UPDATE:
Fabrix, if you have no time to develop this any more can't you release a version that doesn't load up the calendar entries so you will just have a nice clean year view?

Regards.

This review is for a previous version of the add-on (0.4.1). 

Is not a mistery:
Year View was a quick hack, based on month view: it draws 12 mont view, 365+ box, each box with others box and labels. For every refresh it loads all year events for every enabled calendar, sorting them day by day and redrawing all boxes and labels.
Suerly there are better ways to do it, but unluckily I haven't time to take care. But I accept code on github, if you want :)