You are not required to use the viewcube to disable progressive refinement:
juste disable/click on the hollow cube icon below the timeline, left to the "Add Time Tag" button, it toggles progressive refinement.
Be aware that this a per viewport setting and that after loading a scene, the icon does'nt always update. So it might still look disabled while progressive refinement is actually actvate: so click on it just to make sure that it's off...
BTW: With the Direct3D display driver active, the same icon is responsible for the adaptive degradation feature to enhance display performance. So don't get confused by this "great" UI design...
Josef WienerroitherSoftware Developer & 3d Artist Hybrid