In Solid Edge 18, the 3D technology features, the SmartStep headband remains grayed out and I can't change the colors of the selected objects. So when I draw a line, the line is only displayed at the end of the operation after clicking to accept. For circles or others it's identical.
How do you manage to run solidEdge V18 on windows 7? It seemed to me that they were not compatible. Doesn't your concern come from this incompatibility?
After that, you may have to look at the graphics card, especially the driver update. Not being on solidEdge (but on solidworks) for 6 years, I am not going to be of much help to you.
I hope that the users of this software, who are registered on LYNKOA, will answer you.