Comment 0 for bug 59622

The default way to emulate a three buttons mouse is to use touchs F11 & F12. that make the buttons very anti-ergonomic.

an other way (i personally ever do that modification) is to use
that lines in /etc/sysctl.conf:

dev/mac_hid/mouse_button_emulation = 1
dev/mac_hid/mouse_button2_keycode = 97
dev/mac_hid/mouse_button3_keycode = 100

that way we cant use touchpad with right hand and buttons with left hand, without breaking the arms...