Native xterm mouse scrolling in tmux

To scroll within history of the output You would use ^b + [ You can then use M+V to page up and ^V to page down. I don't know if You can use the real PgUp and PgDown though. My terminal does not send these keys to the tmux. Instead it scrolls itself and not the tmux history.

To exit the copy mode, press ESC

To use your mouse in this mode (called copy mode) press ^b + : and enter following:

setw -g mouse on

Note: In tmux < 2.1, the option was named mode-mouse, and not mouse

Now when You change to the copy mode you can use your mouse to scroll through it. You can put this command in your ~/.tmux.conf if You want so it loads every time You run tmux.

Update: As of tmux 1.5 this option makes using the scroll wheel automatically switch to copy mode and scroll back the tmux scrollback buffer. It is not necessary to first hit Ctrl-B + [ any more. Scrolling back down to the prompt also ends copy mode automatically.

I think you need to remove the line

set mouse-utf8 off

My environment is similar to yours. I use Ubuntu 12.10, Tmux 1.7, Gnome-terminal and Konsole. I don't have this problem without this line. I have not found character setting in Gnome-terminal but in Konsole it's Utf-8.

Side note: Don't use mouse, keyboard is much much faster.