Das Werkstatt

Since Thunderbird v45, Mozilla has changed the behavior for writing text:

Return/Enter in composer will now insert a new paragraph by default (shift-Enter will insert a line break)

Maybe that's a good idea for some, but I find it quite annoying.

In order to disable it, do the following:

• Open "Menu > Preferences"
• Choose "Composition > General (tab)"
• De-select the option: "Use Paragraph format instead of Body Text by default"

NOTE: This will not affect drafts already created before changing this.