...If you want to change your default editor simply put a line in ~/.bashrc that changes it. The recommended version of tmux to use is 1.8 or later, with the exception of 2.5, which is not supported (see issue 536 for details). Your mileage may vary for earlier versions. Refer to the FAQ for any odd behaviour. Your distribution's package manager may install the completion files in the appropriate location for the completion to load automatically on startup.