Something has gone haywire with my model. It no longer centers no matter what view I go to. I tried rebuilding the part, but that didn't help.  It would appear that something is out in space that would cause the view extents to center about that boundary limit. But I have checked item in the tree including datum planes and all components are accounted for. I tried to roll back the assembly, but I can't get the bar to move upward. Is there a way to highlight everything to see if something highlights outside of the extents of the model? If this is not a bug, then it should be.