User Agent: Mozilla/5.0 (X11; Fedora; Linux x86_64; rv:59.0) Gecko/20100101 Firefox/59.0 Build ID: 20180327091415 Steps to reproduce: Styles of option-elements are no longer shown by FF. According to W3C HTML Standards of the option element: https://www.w3schools.com/tags/tag_option.asp The style attribute is a valid attribute due to the Global Attributes rule: "The <option> tag also supports the Global Attributes in HTML." Example: <option style="background: #f00">Some Text</option> Actual results: Example: ... 20+ other options elements ... <option style="background: #f00">Some Text</option> ... 20+ other options elements ... and the element does not have any color set, when shown, which is simply wrong. Expected results: FireFox should not ignore the style attrubute, as a) rendering options with styles if a long term behavior of FF b) Chrome does not ignore styles in optpions either. c) the actual W3C HTML standard enforces a style attribute of option elements. Checked and Verified on: 9.4.2018 12:17 CEST

FWIW, https://www.w3schools.com/ is not affiliated in any way to the w3c or any other standards organizations. It's also not a great reference.