<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul" xmlns:html="http://www.w3.org/1999/xhtml">

<bindings xmlns="http://www.mozilla.org/xbl">
<binding id="a" inheritstyle="false">
<content>
<style xmlns="http://www.w3.org/1999/xhtml">
window::after, box::after, bindings::after { content:"m"; float:right;}
</style>
</content>
</binding>
</bindings>

<box style="-moz-binding:url(crash1.xul);overflow: scroll;"/>

</window>