I also faced this confusion! Both with the Enable Touch Widgets / Onscreen Buttons options, and with seemingly random events firing whilst adjusting controls.
One tip I wish I knew before I got some hardware for my Zynth was the keypad/keymapping integration. In this thread @jofemodo recommends a keypad like this but any keyboard will work. The mappings are customisable in webconf.
It won’t fix the button toggle bug, but it might make using the Zynthian more enjoyable.