I have a 2K 27" monitor, which let's face it in 2019 only just constitutes high dpi. The entire interface of Thunderbird is too small. Icons are unclear, font is small and I'd actually like to be able to change the font. I've seen advice to change this via an addon. This seems strange. UX dpi optimisation forms core functionality and should not be an addon (a) it is the case that major updates sometime break addons, as is the case with "Theme font and size changer" addon; it is of further note that the "Theme font and size changer" addon that I was using broke all other themes, so the dark theme didn't work. If I am missing some basic function to allow me to zoom the entire app's UI, please let me know. I'm considering other apps but don't really want to leave 'open-source'. Hope this is fixed soon, thanks -J