I knew I saw a way to interact with it through the mouse. Thank you for reminding me. `tmux` is really a neatly little program, everything is there, simple and efficient.
ps:
man tmux | grep "mouse-" # shows the mouse related options
C-b : "set mouse-<option> on"
pps: turning on mouse windows/panels interactions disable text selection, do you know a way to have both ? (beside switching beside custom defined modes on your .conf)