The solution that worked was to use about:config. Searching for Newline produces the variable editor.singleLine.pasteNewlines. When I go there now, I find that the variable can be Boolian, number, or String. IDK why.
The default value I discovered was Boolean, 2. This was giving me triple spacing on pressing the enter key twice. In most places a single enter key gives a new line and a double enter key press gives single spacing. I changed the default to 1 without changing the variable attribute from Boolean. This yielded double spacing with a single key press. I then tried changing it to zero without effecting any change in result.
I think by changing the attribute to number and setting the value to 1 is working, but I'm curious about how that variable can have all 3 attributes: Boolean, number, and string. Can anyone educate this old man?
