I started to use byobu, and find the it really cool thing.
It has a lot of hot keys. But I couldn't find one of them, and I stuck with one tricky point.
With F2 - you create a new window, but how to close this window when you don't need it anymore?
Later I found cool analogy for new window creation - just divide window and - shift-F2
And you can revert it back - ctrl-F6.