example2.xul

<?xml version="1.0"?>
<?xml-stylesheet href="chrome://global/skin/" type="text/css"?>
<window id="yourwindow" xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">

<groupbox>
  <caption label="Login"/>
  <grid>
    <columns>
      <column flex="1"/>
      <column flex="2"/>
    </columns>
    <rows>
      <row>
        <label value="ID"/>
        <textbox id="id"/>
      </row>
      <row>
        <label value="Password"/>
        <textbox id="password" type="password" />
      </row>
    </rows>
  </grid>
  <button label="Login" />
</groupbox>

</window>