Oops, I must've forgot to check the legacy version when I checked if everything still worked after the "references are a real data type now" update...
It's an easy fix at least, remove all the minus signs from setting up the buttonevent array and then in the one mouse event in that object (which handles actually clicking the buttons) replace the line 18 "if(bev < 0){" with "if(!is_real(bev)){". I'll get a fix for this up ASAP.