I’ve been playing with the new builder for a bit and one thing that caught me was that there is no apply/save button. It appears the editor auto-saves everything on the fly. While this may seem like it’s a nice feature it negates the ability to back out of a change that broke a layout.
On a number of occasions, I’ve done something in the editor that has destroyed the entire layout without the ability to undo what I just did. In the old days, I would just hit cancel and that was that. Go back to the editor and try again/something else. Now that failsafe is no longer there. Once the change is made it’s saved. You have to start over from scratch.