Me too—I updated from Parallels Desktop v.16.x to v.16.1.0, which automatically updated the version of Parallels Tools too. Now all Paratext windows are either solid black or solid white.
I tried two things which were unsuccessful in fixing it:
(1) I held down shift while starting Paratext, and “reset settings”. Didn’t help
(2) Click the hamburger/menu icon at the top left Press down arrow 5 times and then enter. This will open the “Paratext Settings” dialog box, which displays OK.
Uncheck “Enable Hardware Acceleration”, Click OK. Restart Paratext.
Problem remains.
Paratext 9.0.103.41
Windows 10 version 2004 Build 19041.572 <— I just noticed today that Windows 10, version 20H2 has been released. Perhaps I’ll try an update.
Parallels Display Adapter v.16.1.0.48950
In another VM in which I was also too slow to cancel the Parallels Tools update, Paratext 8.0.100.98 still works OK.