Lately, for some reason, when I open a model and middle click to pan/orbit, the model won't move, or it moves with a "hinge" attached to a distant locatioin on the x axis. I have no stray geometry of any mass/volume that should be dominating the model's CG.

I've tried selecting other areas of my drawing, way out at x=0 and at mid locations of my model. No joy. I've drawn and selected random lines at random spots to try to determine where the CG is trying to fix itself other than the one x location. No joy.

Depending on the geometry I'm working with, a middle-click pan/orbit attempt appears to not respond, and it's maddening because the mouse actually IS locking on to something, but it's so massive that the GUI won't respone. Wild panning attempts do nothing.

The ONLY way I've managed to terminate the problem is to create a new, blank drawing and then just close it. That was not specifically scientific or "smart" on my part. It was just dumb luck while copying and pasting stuff to a new drawing to determine what is carrying over.

This "method" is per-session.

Only think I can think of is something recently installed might have clobbered a windows dll...

win 7, SLT 8, v 8.0.0. I've checked all the varioius Preferences settings, and nothing in them seem to offer any help.