See the Thunderbird 45 Release Notes:

The Thunderbird composition window now functions more like a word processor in that pressing the "Enter" key inserts a new paragraph, pressing "Shift+Enter" inserts a new line. This new behavior can be switched off in the Tools > Options > Composition > General tab.

Need to change line height, NOT the behavior of newlines. Cutting and pasting text from other documents, need to preserve line spacing.

Surely SOMEONE knows how to change line spacing?

Pasting a single line spaced list from word results in 1.5 cm spaces between the lines in thunderbird compose window! (In word the para format is single line spacing, no paragraph padding.) Is TB the only application since 1980 where you cant manually fix or change the line spacing??? Even wordpad can do this!

(In the example below: removing the bullets in word before pasting resolved the problem, it then pasted as single line spacing)

Hi Barbara, can you please assist with instructions to preserve line spacing when pasting? ( ... or have you got the same problem?)

Barbara_McHugh said

Need to change line height, NOT the behavior of newlines. Cutting and pasting text from other documents, need to preserve line spacing.