I am having trouble with my screen not refreshing after I nwc a few times and also after making section views using the fabrication section tool.  I am using autocad 2016 with the fabrication cadmep add on and for the computer it is a Dell Percision M6800, I7 2.80ghz, 32igb ram, windows 10 64 bit naidia quadro k4100m.  This is happening in model space I draw with 2 viewport one set to plan view and use the other one for section viewing and isometic.  I have to save the drawing then close it and reopen it to fix it for a little while then it happens again.  This is really frustrating.  I know other have had this problem so someone has to of figured it out already.