[breaking change]: Removed the hide expand sidebar button

src/browser/app/profile/zen-browser.js

@@ -94,9 +94,8 @@ pref('zen.view.compact.toolbar-flash-popup.duration', 800);
 pref('zen.view.compact.toolbar-hide-after-hover.duration', 1000);
 
 pref('zen.view.sidebar-height-throttle', 200); // in ms
-pref('zen.view.sidebar-expanded', false);
+pref('zen.view.sidebar-expanded', true);
 pref('zen.view.sidebar-expanded.on-hover', false);
-pref('zen.view.sidebar-expanded.show-button', true);
 pref('zen.view.sidebar-expanded.max-width', 400);
 
 pref('zen.view.show-bottom-border', false);

src/browser/base/content/zen-styles/zen-sidebar.css

@@ -32,12 +32,6 @@
   }
 }
 
-@media not (-moz-bool-pref: 'zen.view.sidebar-expanded.show-button') {
-  #zen-expand-sidebar-button {
-    display: none !important;
-  }
-}
-
 /*#zen-profile-button::before {
   background: transparent;
   border-radius: 50%;

src/browser/components/preferences/zen-settings.js

@@ -1000,11 +1000,6 @@ Preferences.addAll([
     type: 'bool',
     default: true,
   },
-  {
-    id: 'zen.view.sidebar-expanded.show-button',
-    type: 'bool',
-    default: true,
-  },
   {
     id: 'zen.view.sidebar-expanded',
     type: 'bool',

src/browser/components/preferences/zenLooksAndFeel.inc.xhtml

@@ -290,9 +290,6 @@
       <checkbox id="zenLooksAndFeelNewtabUnderLastTab"
             data-l10n-id="zen-vertical-tabs-newtab-under-last-tab"
             preference="zen.tabs.show-newtab-under"/>
-      <checkbox id="zenLooksAndFeelShowTabExpandButton"
-            data-l10n-id="zen-vertical-tabs-show-expand-button"
-            preference="zen.view.sidebar-expanded.show-button"/>
     <hbox class="indent">
         <checkbox id="zenLooksAndFeelShowBottomBorder"
                 data-l10n-id="zen-vertical-tabs-show-bottom-border"