I am seeing this in Firefox as well. To articulate the problem further...
Drop a relation attribute on a form section. It seems not to matter what attributes you define for display. If you provide no width for the relation attribute, it seems the attributes within the list eat up miles of width and make for a useless display. You can resolve this by defining a width for the relation attribute that fits in the area where it resides.
If you do this in IE, the relation attribute list behaves very well, using up its available width and listing its internal attributes just fine. Chrome and Firefox are having trouble with this.
The work-around is to define your relation attribute widths about 50-75 pixels listt that the screen or Separator they are on.