While creating posts for bug reporting, I noticed that the behaviour for the 'Indent Left' and 'Indent Right' buttons is reversed. Usually, Indent Right will push the text to the right, and vice versa. However, the behaviour of these buttons are switched, such that Indent Right pushes the text left, and vice versa.
I'm not sure if this applies to the post editor in other areas of the site, but definitely applies to the editor when creating a new topic in a forum.
Found in Chrome on Windows 7