Most people probably don't realise this, but this forum has had two editors for a number of years. One is the xenForo default editor, and the other is a custom editor I made years back I called BBCEd.
All the settings for which editor you use was lost during the upgrade. You can find the setting under Account Settings > Preferences > Editor.
Hidden text highlight (or click) to view:
http://www.fanfiction.net/u/2135344/ My Fanfiction account where I have some stories.