Running Ubuntu 22.10, Mate desktop environment. I installed boinc-client and boinc-manager via apt. All works fine in this pre-release version of BOINC (7.20.2+dfsg), except, when I open the Computing Preferences, I get a blank dialog box, with only the window controls in the title bar.
Searching here I found question 1134597 (Unable to access settings of the BOINC manager), which seems to be the same issue from 2019, never answered.
For the time being I used cpulimit to force down CPU usage, but that's not a very polished or ideal way to handle this.