of only when a tab is individually closed.

history window now has a calendar; tons of cleanups, comments, better varnames and in general better quality of code; also a fixme for another day

Check the window's _travel callback matches what we are trying to browse.
(Prevent the window from creating two browsers)

if you want to kill gajim this does nothing. just ash htop the PID of python proc that runs gajim and kill -9 PID