My base dwgs is an assembly of  dwg exported from another software package.  The base dwg has two sub assemblies that are dwgs referenced in that software package.  The base with reference is exported to a dwg format.

When I open the base dwg in draftsight there is a border around the subassembly dwgs.  These are not reference drawings added in draftsight.

The subassemblies show up as blocks in draftsight.  

How do I turn the borders off on these blocks?

I am in mac draftsight.