In the calendar print dialog, the From and To dates can be set.

Incorrect. The print dialog has three options, List, Week, Month Only the Week option allows for changing dates, but each start date is a Monday and each end date is a Sunday. There is no way to print a single day.

Completely unacceptable

Also, completely unacceptable sending emails from no-reply@mozilla.org

Incorrect. The print dialog has three options, List, Week, Month Only the Week option allows for changing dates, but each start date is a Monday and each end date is a Sunday. There is no way to print a single day. Completely unacceptable

I use the 'List' option because then you can select the day. Another alternative I used before is create a screenshot and print it. I have used Paint to modify what it shows.

AS for 'completely unacceptable' - yes it would be more convenient to be able to choose a day configuration. But you need to understand, we can only offer help on what exists or how we - as fellow Thunderbird users - get around the issue.

Also, completely unacceptable sending emails from no-reply@mozilla.org

When comments are posted into your question on the Support forum, a copy of the comment gets sent via email to you because it is assumed you would want to know when someone is trying to offer some help in the Support Forum. This saves you from constantly checking the Support Forum. Those emails are not something you can reply to because all comments need to be created and posted in the question in the forum. There is no email service with mozilla or thunderbird, you are not part of a unique group or mailing list. It's a public support forum on a website. The emails you receive are just a mechanism so you are kept in the loop. Hence why there is always a link in the email to get directly to the question you asked. That link makes it more convenient and speeds up the process.