Layers classes

In addition to the list of upper level's layers there are added the layers of lower levels called classes. Layers together with classes form a tree of layers. In the Layers bookmark there is added the Classes button for editing a tree of layers. In the object description the name of a layer of upper level and the name of the lower class is displayed. At a choice of an object class in the list all tree of classes of a current object layer is displayed.

Classes can be added (by button «New»), edited («Write») and deleted. The class is added into the first selected layer or a class as a child one. Objects that are not included into the classes belong to the top layer. To move an object from a layer into a class or from a class to another class, you can drag the selected objects by the mouse.