Issue 5495 - Action bar shown with white text

mobile/android/base/resources/values/themes.xml

 <?xml version="1.0" encoding="utf-8"?>
 <!-- This Source Code Form is subject to the terms of the Mozilla Public
    - License, v. 2.0. If a copy of the MPL was not distributed with this
    - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
 
 <resources>
 
     <!--
         Base application theme. This could be overridden by GeckoBaseTheme
         in other res/values-XXX/themes.xml.
     -->
     <style name="GeckoBase" parent="Theme.AppCompat.Light.DarkActionBar">
         <item name="windowNoTitle">true</item>
         <item name="windowActionBar">false</item>
         <item name="android:windowContentOverlay">@null</item>
     </style>
 
     <style name="GeckoDialogBase" parent="@android:style/Theme.Dialog">
         <item name="android:windowNoTitle">true</item>
         <item name="android:windowContentOverlay">@null</item>
     </style>
 
     <style name="GeckoTitleDialogBase" parent="@android:style/Theme.Dialog" />
 
     <style name="Gecko.Preferences">
         <item name="windowActionBar">true</item>
         <item name="windowNoTitle">false</item>
-        <item name="actionBarTheme">@style/ThemeOverlay.AppCompat.Dark.ActionBar</item>
+        <!-- Changed theme. See https://issues.adblockplus.org/ticket/5495 -->
+        <item name="actionBarTheme">@style/ThemeOverlay.AppCompat.ActionBar</item>
         <item name="actionBarStyle">@style/PreferencesActionBar</item>
     </style>
 
     <!--
         Application Theme. All customizations that are not specific
         to a particular API level can go here.
     -->
     <style name="Gecko" parent="GeckoBase">
         <!-- Default colors -->
         <item name="android:textColorPrimary">@color/primary_text</item>
@@ skipping 75 matching lines @@
         <!-- Using ABB color palette. See https://issues.adblockplus.org/ticket/3769 -->
         <!-- Set the app's title bar color in the recent app switcher.
 
              Note: We'd prefer not to show up in the recent app switcher (bug 1137928). -->
         <item name="android:colorPrimary">@color/abb_background_light_grey</item>
         <!-- We display the overlay on top of other Activities so show their status bar. -->
         <item name="android:statusBarColor">@android:color/transparent</item>
     </style>
 
 </resources>