Doing a very cursed thing because people keep asking me to make my NearDrop app work on Catalina (would be funny if it overwrites my Mojave install anyway, it really acts like I'm not supposed to have multiple OS versions on a single Mac, even though this is what Apple officially allows)
I did make it work in the end. I don't know why the background is peeking through. Enabling layers for these NSTextViews didn't do anything. If anyone with expertise in Apple UI frameworks knows how to fix it, please tell me. It doesn't do this on Ventura.
Now I can safely forget about this project for 6 more months, until Google breaks their shit on the Android side again.