You say you send a message from your desktop. Does that mean you have an icon for Thunderbird on your desktop?

From the Thunderbird email program on my desktop computer. Yes on my computer. Thunderbird is there (as well as many other program icons). I have been using Thunderbird and Firefox for years.

I thinnk I did solve the problem myself after looking at the help response called "Address Fields: To, Cc, Bcc". You most likely know this but when I saw all the BCC's one one line I realized that the BCC's are not listed vertically as in days of old. Obviously this changed at some point and was addressed in an update doc. I never read those. Too complex and long. [BTW - I could help edit those...]

Anyway, I did figure out one just needs to hit "Enter" after each entry and can then add someone.

And, guess what? I now see this addressed above in this section.

So my bad!

I have now learned how to interact with Mozilla. I really appreciate your prompt response!

I thinnk I did solve the problem myself after looking at the help response called "Address Fields: To, Cc, Bcc". You most likely know this but when I saw all the BCC's one one line I realized that the BCC's are not listed vertically as in days of old. Obviously this changed at some point and was addressed in an update doc. I never read those. Too complex and long. [BTW - I could help edit those...]

Yes it did get a mention back in 2020 when V78 was released https://support.mozilla.org/en-US/kb/new-thunderbird-78#w_new-addressing-area

Thank you for you offer of assistance in document editing. https://support.mozilla.org/en-US/kb/edit-knowledge-base-article

Detailed information on most aspects of the process are here https://support.mozilla.org/en-US/products/contributor/kb

Note that edits require approval and that will only be granted if the edit meets the requirements shown in the detailed documents I have linked to.