Hi List, I am an old user for Thunderbird and moved to Mac OS recently from Linux. The problem I am facing with thunderbird is extremely small fonts on El Capitan. Please see attached photo. The GUI fonts are so tiny that it's mostly unusable. Interestingly, the problem goes away when I connect my mac book pro (2015 model) to external monitor (1680 x 1050 ). Unfortunately, my 24 inch monitor doesn't fits my bag, if I have to work from outside home. I used "Theme and Font Size changer" tool to fix the problem. But then the fonts and GUI is extremely large on my monitor. I believe Thunderbird should show normal fonts on both native display and external monitor like all other apps. Therefore need you suggestions on how can fix these problem. Bade