So this is my problem too but somehow I've managed to do it.
I've went into the Mission Control state and dragged the Neon app into a new screen. It was a pleasant full-screen experience with only the app full-screen and not an individual tab, which is what I expect from the full-screen mode.
Problem is when I tried it again, it didn't work. Not sure what's wrong but this is a newly released software so I'm sure they'll fix it.
Apart from that, it's really amazing. I especially LOVED the media control features.
edit: Got it now. Go into the full-screen mode when there no active tabs. Works perfectly after that.
I've went into the Mission Control state and dragged the Neon app into a new screen. It was a pleasant full-screen experience with only the app full-screen and not an individual tab, which is what I expect from the full-screen mode.
Problem is when I tried it again, it didn't work. Not sure what's wrong but this is a newly released software so I'm sure they'll fix it.
Apart from that, it's really amazing. I especially LOVED the media control features.
edit: Got it now. Go into the full-screen mode when there no active tabs. Works perfectly after that.