The option called "multiple work" is a great feature which can be improved a bit. my case: i´m giving sessions of 2hours length, and info-talks of 30min length.
if a timeslot is blocked by a info-talk, the timeslots previous to this can not be used for the sessions.
Actually the time, which i can not(!) select, appears in the time-table and when selecting it the popup "You can't select this time slot!'"  In this case it would be helpfull if the time-slot is not displayed.. 

at all: thanks a lot for your excellent work!
all the best, ramos