In version 2019.2.3871 when I resize the div my calendar is in, the headers do not resize properly anymore. Is there a functionality change that I am missing or did this break?
It still does not resize in the newest available build
Add on. This happens on the week view and resource view(Day) but the month view works properly
If you resize the window the change will be detected automatically using window.onresize event handler. In other cases, you can call DayPilot.Calendar.show() to fix the view (https://api.daypilot.org/daypilot-calendar-show/).
The Scheduler uses autodetection for these cases as well and it's likely that it will be ported to the Calendar in the future.