Full screen issues...black blinking lines all over at full screen

[DrKevin]

Hi, I'm trying to run ksp 1.11.0 on my Imac (iMac Retina 4K, 21.5-inch, Late 2015), running Catalina.  When I go full screen, hordes of blinking black lines appear.  I tried to change the resolution, which works somewhat, but then the buttons and pop up dialogue become too small to see.  Is there a fix to this or a suggestion for my machine?  I've resorted to booting ksp from the ksp launch program using launch to full screen.  Not the best solution because A) it's not full screen, just a large enough window and B) the resolution is much lower.  any ideas?

thanks