I haven't changed anything, just downloaded and launched, that's the result. if the term only works with one font why is the software picking a random one from the system conf?
It looks like refterm is hard-coded to use Cascadia Mono, which isn't included in-box with Windows 10. So I don't know what happens if you don't have that font. If that's the only issue, then I think we can let that one go, as refterm is clearly only a proof of concept, and one-time logic for choosing the correct font at startup would presumably have no effect on rendering speed.
It looks like your "Digit grouping symbol" field is empty. I'm sure that's standard in some locales, though not for US English. I don't know how to make that field empty; when I try, Windows says it's invalid. So I wonder if your locale sets that separator to some kind of Unicode character that, in a proper renderer, is equivalent to no character at all. If that's the case, then I'm guessing refterm could handle that character as easily as it handles VT escape codes. But this does lend some weight to the position that Casey was oversimplifying things a bit.
Their settings aren't wrong, just different, likely because of differing standards for digit grouping across locales. So this is a case that refterm clearly doesn't support. This case by itself doesn't invalidate refterm's approach to rendering, but I can see why the team at Microsoft, knowing that there are many such cases, would favor abstraction over the absolute best possible speed.
