tmux hightlight colour setting In `tmux`, the default highlight setting is a yellow background -- at least on my version and machine. This is when using the mouse on X11 but is the same with the console selection. I cannot find the option to change this in the man page. What is the option to change this?

The option you're looking for is called `mode-style`.

For example, entering `:set mode-style "fg=red,bg=blue"` in the `tmux` command prompt and selecting something from `man tmux` yields the following result:

!tmux mode-style demo screenshot

Note that this option also affects the display of the line counter (here `[0/11]`) in the upper right corner of the pane in copy-mode.