This is what I do for nested sessions:

  bind -n S-up \
  set -g status-bg white \; \
  set -g prefix None

  bind -n S-down \
  set -g prefix C-a \; \
  set -g status-bg green

Press Shift-ArrowUp, and all control will be passed to the nested session.

Ah, that's smart, thank you! Looks like it would work especially well for multiple levels of nesting.

I've also tried the status line indicator but it's difficult to balance between being too visible and invisible. So just leads to doing the right commands on the wrong session. Though I find any nested session is rarely needed. I mean locally, a session is a window so I do that.

I haven't had a problem with indicator visibility, but I remember spending some time getting it to a place that worked for me.

Here's what I use:

  set -g status-left "#{?client_prefix,#[bg=colour76]^,#[bg=colour235]_} [#S]"
  set -g status-right ' | #[fg=colour76]#h#[fg=default] %H%M%Z'

Right side included just for completeness. The conditional colour setting was the useful part, IIRC.

I don't mean rendering of an icon so much as I mean that humans become blind to persistent things (and frequent things). Losing glasses on your head kinda thing. I don't find a mirror as helpful as having a fixed location to put my glasses when I'm done with them. Same strategy

But yeah, when I didn't have splits and things in my emulator I used something like you did. Make a remote section visually distinct. To a lot of extent I still do, just this isn't necessary through tmux anymore