Ok, I'll try in here. Upgrading to Parallels 16 and v16.x of toolbox has made it so my multi display in Ubuntu 18.04 no longer functions properly. Everything was jiving back in P14 and I had upgraded to Catalina with 14, and then with Big Sur, 14 was no longer an option, so I upgraded to 16. All of my Guest OS's I've upgraded to toolbox v16.x have had this issue. I have one Guest OS that's running p14.x toolbox(because I figured I'd try it out and not upgrade it) with P16, and multi display is working just fine. Any tips on how I might be able to fix this on my other Linux Guest OS's? Thank you
