I'm testing on mediawiki.org but am creating a bug report since these haven't been mentioned before so I don't believe they've been fixed in git.
If I try to paste some text in the editor, the paragraphs in it get stuck together, and it gets '↵' character inserted periodically, at places not corresponding to any line breaks in the text. Example:
If you want your user to be able to configure your extension, you'll ↵need to provide one or more configuration variables. It is a good idea ↵to give those variables a unique name. They should also follow MediaWiki↵ naming conventions
This happens both with pasting with Ctrl+v and with mouse. Firefox 16.0.1 on Windows XP SP 2.
Version: unspecified
Severity: normal