gecko/toolkit/content/customizeCharset.xul

<?xml version="1.0"?>

<!-- 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/. -->

<?xml-stylesheet href="chrome://global/skin/" type="text/css"?>

<!DOCTYPE dialog SYSTEM "chrome://global/locale/customizeCharset.dtd">

<dialog xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
        title="&title.label;"
        onload="Init();"
        ondialogaccept="return Save();"
        persist="width height">

  <script type="application/javascript" src="chrome://global/content/customizeCharset.js"/>
  <script type="application/javascript">
  <![CDATA[
    var observerService = Components.classes["@mozilla.org/observer-service;1"].getService(Components.interfaces.nsIObserverService);
    observerService.notifyObservers(null, "charsetmenu-selected", "other");
  ]]>
  </script>
  
  <!-- The two-pane -->
  <hbox flex="1">
    <vbox flex="1">
      <label value="&additional.label;" control="available_charsets"/>
      <!-- Available Charsets Tree -->
      <listbox id="available_charsets" flex="1" seltype="multiple"
            onfocus = "document.getElementById('active_charsets').clearSelection(); this.selectItem(this.currentItem || this.getItemAtIndex(0));"
            onselect="update_buttons();"
            ondblclick="AddAvailableCharset();"/>
      
      <separator class="thin"/>
      
      <hbox align="center">
        <button id="add_button" oncommand="AddAvailableCharset();"
                label="&add.label;" icon="add"  accesskey="&add.accessKey;"/>
      </hbox>
    </vbox>
    
    <separator orient="vertical"/>
    
    <vbox flex="1">
      <label value="&current.label;" control="active_charsets"/>
      <listbox id="active_charsets" flex="1" seltype="multiple"
            onfocus = "document.getElementById('available_charsets').clearSelection(); this.selectItem(this.currentItem || this.getItemAtIndex(0));"
            onselect="update_buttons();"
            ondblclick="RemoveActiveCharset();"/>
      
      <separator class="thin"/>
      <hbox align="center">
        <button id="up_button" label="&moveUp.label;" icon="go-up"
                accesskey="&moveUp.accessKey;" oncommand="MoveUp();"/>
        <button id="down_button" label="&moveDown.label;" icon="go-down"
                accesskey="&moveDown.accessKey;" oncommand="MoveDown();"/>
        <button id="remove_button" oncommand="RemoveActiveCharset();" icon="remove"
                label="&remove.label;" accesskey="&remove.accessKey;"/>
      </hbox>
    </vbox> 
  </hbox>
</dialog>