Detailed month view for label has for=”course”. The associated select has a name of course, but id is different so the label is not associated.
For a <label> to work properly, it must include a for attribute, which identifies the <input> to which it is associated. The for attribute's value should match the id (not the name) of the <input> element.
The “New event” button activates a pop-up which is exited immediately.