Xref Layers - Xref

When you attach or overlay a drawing reference, the drawing objects and named objects (layers, blocks) also go into the host drawing

A special prefix is added to any named objects from the reference drawing
A layer named Door in reference drawing Factory Floorplan would display as Factor Floorplan|Door
You cannot make an Xref layer current in the host drawing
The Xref layer can be Off, Frozen, Lock
If the properties of Xref layer are change, it will not affect the reference drawing, the changes only retained in the host drawing

An Xref filter is automatically created when the drawing reference is attached