Review for Chromatasks by AllieOople
Rated 5 out of 5 stars
Love, love, love this add-on. It takes a little time to set up properly, because you have to assign colors to the different calendars. But once it's done, WOW. The color-coding is great to get an at-a-glance view of what still needs doing.
...BUT, this is not compatible with Thunderbird 60. I rolled back to an earlier version to continue using this add-on, but was wondering if it would be updated to work on 60.
To create your own collections, you must have a Mozilla Add-ons account.