As part of upgrading the Xenforo software, we are also getting a new version of the editor they use (a third party product called Froala). It's a "cleaner, leaner" look that I am not totally sold on myself. The button bars are organized differently (a lot more buttons buried on the three dot extensions) so you may need to do some hunting for your favorites (I will probably do some tweaking, esp. if I get feedback that something is in the "wrong" spot). Preview is now a "tab" in the top right corner instead of a button.