box-sizing: border-box (with its prefixed variants) has been championed by many web heros. As a result, some Joomla templates use it (like a reset, default value). I noticed this property messed up the calendar event box.
So you might want to add box-sizing: content-box to the Calendar to prevent this from confusing users (and also -moz-box-sizing and -webkit-box-sizing).
Hello,
probably you meant our Scheduler. We will consider this issue for future update. Thank you for the suggestion.