steps to reproduce in month mold:

launch a calendar in read only mode -> drag and drop is disabled, no events are fired when clicking somewhere OK
set readonly to false calendars.setReadonly(false) -> drag and drop work, and events are firing OK
set readonly back to true calendars.setReadonly(false) -> drag and drop still work, causing lots of errors at the client site

current workaround to refresh view state, and event bindings on the client side:

calendars.setReadonly(false);
calendars.invalidate();