I've been using MC for Mac since V20 and have used almost every version since then. MC23 keeps my font selection. I'll double check this when I get home, as I haven't changed font faces or sizes since MC22.
I'd like to insure something about your setups though. Are both of you running MC23 from the Applications folder? Or are you running from the mounted installation file (DMG) ?
It will be a few hours, but I will report after I can test.
Brian.
I have two systems running MC23. On one, the font change works just fine. On the other, when I change the font family, it sticks but when I change the font face, it does not. In both cases, I am running from the Applications folder. Interestingly, the system on which the change works is running a High Sierra beta.
I'm changing the font by selecting Tools, Options, Tree & View, and Select Font.
UPDATE: I changed the font on the system that did not work to a different font size and it seems okay now. No idea why.