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 this I
simply added the arrow keys to my .tmux.conf without the -r option:
bind-key Up select-pane -U
bind-key Down select-pane -D
bind-key Left select-pane -L
bind-key Right select-pane -R