> so you want each of the split windows behave like its own session or something, and switch terminals within that freely.
Exactly. Or at least that's one way to describe it, though it might also equally describe other things.
> so how does screen do that?
It's screen's native model.
'C-a |' (split -v) splits side-by-side and 'C-a S' (split) splits top-and-bottom. Screen calls these "regions". 'C-a X' (remove) will remove the current region, letting the sibling take the entire space again. 'C-a Q' (only) will replace the entire layout with the current region. 'C-a tab' (focus) will jump to the next region (it can take directional arguments to move up, down, left, and right, as well as 'prev' to go the opposite way of 'next', but these are not bound by default).
What tmux users would normally think of as window changing commands just switch the current region in the layout between viewing the entire pool of running commands.
that does make sense and i can see that's a useful way to work actually.
so how does screen do that?