ShapeNo
It is the order of MyShapes, delete, add,
sendback,bringtofront,sendbackbystep,bringtofrontbystep will change it.
it is maintaced by TMyCAD and readonly for you, please donot change it.

ShapeId
It is the shape's Id, Delete or add a shape , it is not changed, it is a auto-increment field.
it is maintaced by TMyCAD and readonly for you, please donot change it.

ChildShapeNo
If the shape is a single shape , this field is empty;if it is a grouped or combined shape, this field
will store the child shape no.

UserData
UserData:TUserData;
You can manager yourself data at here, it is very usesful.please read TUserData in help file.