thunderbird

When you reply to a message or create a new message in Thunderbird, the default format is "Paragraph".

To change it to "Body Text", deactivate the "Use Paragraph format..." option under Edit > Preferences > Composition > General, and the default paragraph format changes from "Paragraph" to "Body Text".

I prefer to keep Thunderbird messages bold (unread), until I have opened them by pressing Enter, or marked them read by pressing M.

The only way I have found to get this behavior is go to Edit > Preferences > Display > Advanced, select "Automatically mark as read", select "After displaying for seconds" and enter a very high number in the seconds field.

If you have an image file attached to a Thunderbird e-mail message, it's easy to delete at the bottom of the message, by right-clicking and selecting Detach. But if the image is embedded, you don't have that option.