What do the red rectangles on points mean?

 From:  amur (STEFAN)
6473.1 
Hi Michael,

just curious what those red rectangles in MoI mean, after i used show points, because i never have seen them before. It's just an .iges exported hair curve (from Hair saloon) in Shade.

Best regards
Stefan


EDITED: 30 Oct 2016 by STEFAN