[Rx] Customizing Firefox Quantum

ff002Firefox Quantum is the new and improved version of FF used by all the kool kids. The last few years I’ve been using the Palemoon browser started as a fork of the old pre-29 Australis version and is a bit long in the tooth. The reason I’ve been slow to adopt is that Quantum broke most of the old add-ons, including Del Rio’s awesome Speed Dial. Ultimately, Palemoon seemed to be getting sluggish, so it was time to update.

The goal is to make Firefox Quantum look and function as well or even better than Palemoon…

Firefox Quantum Customization Hacks

No Video AutoPlay

Open up a page and a stupid video starts. This is so annoying. Just turn it off.

  1. In url bar: about:config
  2. Search for: media.autoplay.enable
  3. Toggle: Off



You can change the “look” of Quantum using a custom css file located in a new directory in the profile (userChrome.css). I found this on: https://www.userchrome.org/

Find Profile Directory and Create New “chrome” Directory.

Type about:support in the URL bar.

Click Open folder.


Create chrome directory.

Create userChrome.css file.

This userChrome.css puts the Menu Bar over the Tabs and Rounds the tabs.

/* Replace this SAMPLE CONTENT with your own CSS */

/* No blue swipe on tabs when loaded */
.tab-loading-burst {
   display: none !important;

/* Tab bar below Navigation & Bookmarks Toolbars */
 #nav-bar { /* 
main toolbar */
   -moz-box-ordinal-group: 1 
   box-shadow: none !important;
 #PersonalToolbar { /* bookmarks toolbar */
   -moz-box-ordinal-group: 2 !important;
 #TabsToolbar { /* tab bar 
   -moz-box-ordinal-group: 3 !important;
   padding-top: 0 !important;
 /* Clean up spacing */
 .titlebar-placeholder {
   display: none !important;
toolbarbutton.bookmark-item {
   padding-top: 2px 
   padding-bottom: 2px !important;

/* Vertical space for min/max/close buttons above the main toolbar */
On Mac, if not showing title bar, allow 20 pixels */
#toolbar-menubar:not([accesskey]) ~  #nav-bar {
20px !important;
 /* On Windows, if not showing title bar or menu bar, 
allow 20 pixels */
#toolbar-menubar[autohide="true"][inactive="true"] ~ #nav-bar {
   margin-top: 20px !important; /* More px may be better on Win10 */
Sorry, Linux users, I don't know the best approach for you! */

/* Background for Light and Dark themes */
 #main-window[lwthemetextcolor="bright"] #TabsToolbar, 
 #main-window[lwthemetextcolor="dark"] #TabsToolbar {
   background-color: var(--chrome-secondary-background-color) 
   background-image: none !important;
 #main-window[lwthemetextcolor="dark"] .scrollbutton-up,
 #main-window[lwthemetextcolor="dark"] .scrollbutton-down,
 #main-window[lwthemetextcolor="dark"] .tabs-newtab-button,
 #main-window[lwthemetextcolor="dark"] #new-tab-button,
 #main-window[lwthemetextcolor="dark"] #alltabs-button {
var(--lwt-text-color) !important;
 /* Left and right borders on Win 7 
& 8, but not on 10 and later: */
 @media (-moz-os-version: windows-win7), 
(-moz-os-version: windows-win8) {
   /* Vertical toolbar border 
   #main-window[sizemode=normal] #navigator-toolbox > 
toolbar#TabsToolbar {
     border-left: 1px solid 
hsla(240,5%,5%,0.3) !important;;
     border-right: 1px 
solid hsla(240,5%,5%,0.3) !important;;
     background-clip: padding-box;

/* Override vertical shifts when moving a tab (9 Jan 2018) */
 #TabsToolbar[movingtab] {
   padding-bottom: 0 !important;
 #TabsToolbar[movingtab] > .tabbrowser-tabs {
   padding-bottom: 0 !important;
   margin-bottom: 0 !important;
 #TabsToolbar[movingtab] + #nav-bar {
   margin-top: 0 

/* Curve the background tabs at the upper left and right 
    May not work on add-on themes. */
 .tabbrowser-tab {
   border-radius: 10px 10px 0px 0px / 15px 15px 
0px 0px !important;
 /* Curve active tab and slightly overlap 
neighboring tabs */
 .tabbrowser-tab .tab-background[selected="true"] 
   margin-left: -1px !important;
-1px !important;
   border-radius: 10px 10px 0px 0px / 15px 15px 
0px 0px !important;
 /* Shorten the tab line along the tops of tabs 
 .tab-line {
   margin-left: 9px !important;
   margin-right: 9px !important;
 /* Shorten the vertical lines between 
background tabs */
 .tabbrowser-tab::before, .tabbrowser-tab::after 
   margin-top: 9px !important;

/** "Light" Theme (Dark Text) **/

/* Border the background tabs (10% gray) for greater visibility */
.tabbrowser-tab:not([selected="true"]) {
   border: 1px solid 
rgba(0,0,0,.1) !important;
   border-bottom-color: transparent 
   margin-right: -1px !important;
 /* Remove 
short vertical lines between background tabs */
 #main-window:not([lwthemetextcolor="bright"]) .tabbrowser-tab::before, 
 #main-window:not([lwthemetextcolor="bright"]) .tabbrowser-tab::after 
   border: none !important;

Speed Dial Replacement

While it’s not even close to the power of Speed Dial, there is a Quantum-compatible dial: Quick Dial.


A simple right click allows you to create either a bookmark or a folder.

Once you have a bookmark, you right click it and select Properties.

The links are stored in a bookmarks folder: Quick Dial.

It’s very simple.