The calendar has user-defined colours for the background, the days, the text or one can assign one's own image as a background. There are a number of embedded background images to select from.
It has no title bar yet can still be dragged to any position. Its position is saved when closed, as well as the colours.
The Calendar is meant to run unobtrusively..it does not appear on the dock, nor does it have a menu associated with it. Moreover, after switching the calendar to another month,