At first I thought this was an issue with Windows 10, but then I realized it really wasn't. I am using the Dark Mode in Windows 10. When I right click on the desktop the dialog box renders in darker colors. Also, most all the programs I use take on the same colors, though I believe it is relative to the program and it is relative to Firefox. Consequently, when I am in the Firefox browser and I right click and open a dialogue box in Firefox, the colors are a white background with a black font, on every web site. I then remembered the colors option in Firefox and went to options, fonts & colors and changed the colors to a black font on a white page. I also ticked on Use System Colors as I have done in previous versions of Firefox & Windows. However, they won't take, and my dialog boxes continue to have a white background with a black font. :/ Thank you.