Inspecting the source of an email does not always reveal the plain HTML source, but some encoded byte mess. In order to inspect the HTML anyways, you can use a little trick:

While composing a message, select all (Ctrl + A), then navigate to Insert > HTML on the message window.

Growing Rails Applications in Practice

Check out our e-book. Learn to structure large Ruby on Rails codebases with the tools you already know and love.

• Introduce design conventions for controllers and user-facing models
• Create a system for growth
• Build applications to last

Read more Show archive.org snapshot

If you need to inspect a received message, hit "Reply" to turn it into composition mode.