Useful concept, works perfectly. I had but one humble request though: an option (within a timetable) to show a notification or similar, to differentiate between tabs opened by this addon vs other means, if it's not too difficult to implement.
You might like to try the Option of "Dont load tabs until selected" https://simplebrowsingschedule.wordpress.com/how-to/dont-load-tabs-until-selected/ (although that may or may not suit your particular use case)
