Xresources hates apostrophes in comments
xterm-enabled autocopy to system selection from tmux copy events

normal mouse drag enters copy mode and sends this escape to xterm,
which modifies the x selection for painless copy that respects split
boundaries (unlike shift-drag).

also have 'y' shortcut key to do it from keyboard.

another reason to use xterm (in addition to alt 'just working' in vim)
tmux: escape exits from copy mode