Things you should know Rated 4 out of 5 stars
Things you should know about Thunderbird Lightning Calendar:
Version number: To check the version number of the Calendar Add-on to Thunderbird you have installed, click on Tools > Add-Ons > Extensions.
CAREFUL: If you left-click on a Lightning calendar entry and somehow hit the DEL (Delete) key, the calendar entry will be deleted without confirmation!
Sunbird calendar now obsolete: Sunbird is a calendar application related to Lightning, from the same developers, that runs as an independent program. To have current versions of the calendar, Sunbird users must convert to using the Lightning add-on for the Thunderbird email program. That means they must use Thunderbird.
Export and Import: When exporting .ICS Calendar files from Sunbird so that they can be imported into Lightning, all Calendar event entries that have ever existed appear, even those that were for dates long in the past. It is necessary to change "All Events" (above the heading "Titles" of events) to some other value to hide those events.
Errors: When importing an .ICS Calendar file, the following message appeared. "An error occurred when writing to the calendar Home! Error code: MODIFICATION_FAILED." ("Home" is the name of the calendar.)
Mozilla publishes email addresses: Mozilla publishes the email addresses of those who submit bug reports. This applies to all Mozilla products, not just the Lightning calendar. That policy discourages the submission of bug reports.
Note that Mozilla uses 3 names for what, to the reader, is one thing: Add-ons, extensions, and plug-ins.