Cinema 4D Lite 22.016 viewport has flickering black screen

Running Mac OS 10.13.6 HIgh Sierra with Cinema 4D Lite 22.016.  When moving the cursor off and on the Perspective viewport, it turns all black when I roll on, then appears normal when I roll off (by normal, I mean I can see the perspective grid lines). Roll back on, it turns black again.  Youtube recommended turning off OpenGL in the preferences, but there is no option to do that with Lite. Maybe that's only with the full version.  Even in Preferences, when I uncheck a button, viewport goes black. Recheck button, viewport back to normal.  I'm thinking it's a OS incompatability problem.  I have an older iMac and cannot upgrade past High Sierra.  Any other thoughts would be appreciated.