gecko-dev/mobile/android/base/resources/drawable/menu_item_state.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/. -->

<selector xmlns:android="http://schemas.android.com/apk/res/android"
          xmlns:gecko="http://schemas.android.com/apk/res-auto">

    <item gecko:state_more="true"
          android:drawable="@drawable/menu_item_more"/>

    <item gecko:state_more="false"
          android:state_checkable="true"
          android:state_checked="true"
          android:drawable="@drawable/menu_item_check"/>

    <item gecko:state_more="false"
          android:state_checkable="true"
          android:state_checked="false"
          android:drawable="@drawable/menu_item_uncheck"/>

    <item android:drawable="@android:color/transparent"/>

</selector>