Most of the properties are inherited from the JLabelled drawing class.
There are two types of markers whic can be attached to drawings - fluid and analog connection points. In general, the number of these on the drawing should match the number required by the object for which it is intended, (although the latter will cope of it does not).
The expansionFactor field sets a scaling relative to the efault component size, so, for example a setting of 0.5 would casue the component to be drawn half size compared with other components which had the default expansion factor of 1. When presented as an icon, a value of 1 is always used for the drawing.