Objects, in a QuarkXPress document, can be placed on different layers.
Quark document with 4 layers
Some remarks about layers in QuarkXPress and how they are treated in Q++ Studio:
•Each object belongs to one layer, and its selection marks appear in the color of its layer.
•Layers can be created below the Default Layer.
•All objects of a layer are above all objects of the layer below (in the above example, all object of layer 3 are above all objects of layer 2). This behavior is respected in the generated output files created by Q++ Studio since build 13299 (February 2012).
The one very important exception to the last point above, is that the Default Layer is never ignored by Q++ Studio.