I'm running Parallels 15 on Catalina. Runs Windows and Ubuntu great, and the screen resolution matches the monitor, but the MacOS Mojave VM is at 1024x768 and nothing will change its mind, including running Parallels Tools. I'm stuck. Makes it kind of useless for the work I'm doing. Yes, I went in to the Control Center config on the VM and tried different graphics options, like Retina. Made no difference.