Don,
IE11 is a Windchill (10.1) No No.
We are using Windchill 10.1 M030 with Creo 2.0 M100 and Creo View 2.0 M030.
We have had no issues with IE9, I have IE10 at home and it will hang on some of the APIs (LifeCycle Manager etc.) and I tried IE11 (just for fun) and everything was all #$&^ed up. After removing IE11 and going back to IE9, everything worked again.
Mike Ibosh