When upgrading from tmux 1.1 to 1.5 I found a few key bindings changed slightly. In particular, the arrow keys used to switch panes now repeat. I often use the sequence C-b Down immediately followed by Up and then Enter to re-run a unit test. With 1.5 I was doing this too quickly (tmux’s repeat-time is 500ms by default) so I was switched back to my previous pane. To fix
Today I finally switched my long-running IRC screen session to tmux. I rarely disconnect so I was simply waiting for a “good” time. After a few minutes I noticed that my irssi scrollback was misbehaving; only half of my window would redraw when I pressed PgUp of PgDn. I had manually set TERM=xterm in my bashrc; however, tmux advises only using screen or screen-256color as the term. I have no idea why I had specified term within my bashrc; removing the line and restarting tmux corrected the issue.