What happens when you press page up or down in tmux? Have you configured it to scroll page up & down? Or do you do that via Ctrl-B ] or whatever the magic incantation was?
bind -n S-PPage copy-mode -u
bind -T copy-mode S-PPage send -X page-up
bind -T copy-mode S-NPage send -X page-down
The first line is a top-level binding to enter copy-mode and immediately scroll up one page. The other two add bindings within copy-mode so you can continue to scroll up or down with those keys.I also have a small hack in my .zshrc to start scrolling up with `M-v` (like in Emacs) while at a shell prompt:
tmuxup(){tmux copy-mode -u}
zle -N tmuxup
bindkey '^[v' tmuxupThis is something tmux inherited from screen, but it from a quick test it looks like they didn't copy the whole thing? You use [ to enter this mode (it's actually for copying text, not just scrolling) and in screen use ] to exit without copying anything. Looks like tmux doesn't have ], at least by default?