Not parent but keybindings are fully configurable. For example to scroll up with Shift-Pgup:

    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' tmuxup

I used to do all of this type of stuff to get my copy-paste to work in tmux but honestly it's still a pita. The alternative I started using recently (zellij[1]) has copy and paste, scrollback, dump scrollback to editor etc just working out of the box with no fancy configuration required and also has a much saner session management mechanic that also works right out of the box.

[1] https://zellij.dev/

That's right. You have a prefix that lets you use page up page down in any pane you've got currently selected.

> Ctrl-B ] or whatever the magic incantation was

This 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?

When I used tmux I used to set Ctrl-PgUp/Down bindings to scroll the buffer.

Ctrl-B PgUp/PgDown enters scroll mode.