We just moved from WF4 to Creo 2 m100 yesterday.
Hidden line removal has been interrupted.
Do you want to continue HLR,
switch to wireframe, or cancel this
update of the display?
The first thing that comes to mind is the fast_hlr setting.
The red-X is not new, but it may be that it went by fast enough before it went un-noticed or was fast enough that the time-out before displaying it was longer than the view regen time.
I still recall it from the HP-UX stations. It was quite the time saver when getting to the correct sheet on mult-sheet drawings.