The editor keeps inserting extra lines in my post

I keep drafting my posts, usually I put a single line between my paragraphs, like this (it will probably bug):

But for some reason the forum is expanding each new line to at least one extra line. I thought I was going insane at first, just inserting a bunch of lines because I’ve been working in LaTeX recently which is agnostic to how many newlines you put between things (1 newline does nothing, 2+ is a new paragraph), but no, it definitely happens.
(Note: After posting this, it seems to be limited to the WYSIWYG editor, which is, for some reason acting as the default editor despite me using the markup plaintext editor by default for years here). I’m not deleting the extra lines in this post so you can see the results.

Edit2: I did manage to find the default editor settings in my UserCP, but that doesn’t change the fact WYSIWYG seems broken. Both “Basic Text” and “Expanded” seem to work, only “Full WYSIWYG” does it.

A couple of my other message boards do that. Until it gets fixed, Shift+Enter might give you the single lines you want.

A couple of mine do also. I’ll try Shift + Enter on them. Thanks!

The code for the WYSIWYG editor is so old it doesn’t even work on Chrome.* It wouldn’t surprise me if it’s not adapting properly to modern browsers. I’d guess that pressing “Enter” inserts a <P> tag, which is a new paragraph, rather than a new line.

*I did write a script with keyboard shortcuts for all the buttons, and a side effect is that I can also force enable WYSIWYG mode on Chrome. Some stuff works fine, but other stuff is broken. Basically, anything that requires a dialog box breaks.

BTW, I also added a few extra buttons (spoiler, strikeout, superscript, subscripts). I call it my “S button adder.” All my scripts are available here.