gecko/embedding/android/resources/layout/tabs_tray.xml

<?xml version="1.0" encoding="utf-8"?>
<ListView xmlns:android="http://schemas.android.com/apk/res/android"
          android:id="@+id/list"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:background="#fff"
          android:cacheColorHint="#fff"
          android:divider="#666666"
          android:dividerHeight="1dp"/>