Say you want some window to be available in several sessions. For example I wanted this to have my mutt window available in different sessions.
Of course you can just create a window with a separately running mutt in each session, but while working with mutt it might not suit something else. Also, that isn't a Jedi way anyway.
So, here's the trick. First you create a new session, just as usual:
tmux new-session -s mail
Name it whatever you want, just something reasonable. You can detach from it whenever you want.
Then you attach to the session you currently want to work on:
tmux attach -t my-project
Now, in this session, execute
tmux link-window -s mail:1 -t 0
This will link window 0 in the current session with the window 1 in the session mail.
To unlink, just use
You can bind those commands to some keys if you want:
bind + link-window -s coms:mutt -t 0
bind - unlink-window -t mutt
For further info consult
man tmux of course.
If anyone knows a simpler way to achieve this, please leave a comment.