I had this CSS code in my Firefox chrome/userChrome.css in order to enable walking through tabs by arrow keys:
.tabbrowser-tab[selected="true"] {-moz-user-focus: normal !important;}
After my last upgrade to (Ubuntu 16.04) Nightly 57.0a1 (2017-08-03) (64-bit) it stopped working. Is this code not valid CSS anymore? How to correct this code?