Dragging and dropping an email to the calendar view creates a calendar entry with the email embedded in the description field.This is useful, but the date and time does not seem to depend on the drop position on the calendar. At least, if you drop on a specific day, it ought to pick up that date, but preferably the position on the day should also give the approximate time. At present, the calendar entry seems to default to current date and time which is rarely useful.
Yes, the drop does not recognize the position in the calendar because it simply passes the message to a new event window.