[ajorgensen]

Yeah that makes sense. To me it felt unintuitive that environment was global and only copied on server start, with a few exceptions, and not session start but that was likely just a failure in my mental model of how tmux worked.

[ilyt]

I think it's about the stuff that needs to be shared. Like variables for X11 or ssh agent.

If you start server off your graphic session then any new tmux session will get those variables and your ssh agent or graphical app will "just work".

Reading from current one by default might fuck something up if you say have some automation that starts stuff in tmux

There isn't really good way to handle it by default that would make everyone happy, screen had similar "problems".

I just have

    tmux new-session -d -s main

in my .Xsessionrc so the main session gets both SSH_AGENT stuff (I use gnupg as agent, for smartcard support) and proper DISPLAY, then just use alias to use that main session