It looked as if it would be so simple when Mojave introduced Dark Mode, didn’t it? After all, it’s just a control in a System Preferences pane. Sure, everyone anticipated there’d be issues with document formats which were pernickety about colours, like web pages and PDF. But ordinary, common or garden Rich Text?
Eighteen months later, Rich Text remains a real mess in Catalina’s Dark Mode. Apps that work with what macOS terms Attributed Strings handle their non-coloured text one way, and those like TextEdit do something completely different. Some QuickLook thumbnails don’t work properly, while others do. In short, Apple hasn’t tidied up the loose ends even in macOS 10.15.3.
You can catch a glimpse of these problems in QuickLook thumbnails, as shown in the Finder, and in previews. Apps which handle Attributed Strings and then write them out directly to RTF files generate their uncoloured (black/white) text in bimodal form. In QuickLook thumbnails viewed in Light Mode, these look fine.
Read more at EclecticLight.co