2D constraints to a block

 I am trying out v17, and attempting to create a drawing that makes extensive use of 2D constraints.  However, I am unable to create a dimensional constraint between the end of a line object, and a block.  This is true regardless of if I choose to snap to the end's of one of the lines in the block, or to the insertion point of the block.

I just confirmed that AutoCAD does permit you to use 2D constraints with blocks.  Is this a limitation of BricsCAD?  Attached is the example drawing.

-Joe