Firefox 这个xul覆盖有什么问题？

我试图在Firefox开发工具中添加一个“编辑html”按钮。在里面chrome://browser/content/devtools/inspector/inspector.xul 我们有：

  <popupset id="inspectorPopupSet">
    <!-- Used by the Markup Panel, the Highlighter and the Breadcrumbs -->
    <menupopup id="inspector-node-popup">
      <menuitem id="node-menu-copyinner"
        label="&inspectorHTMLCopyInner.label;"
        accesskey="&inspectorHTMLCopyInner.accesskey;"
        oncommand="inspector.copyInnerHTML()"/>
      <menuitem id="node-menu-copyouter"
        label="&inspectorHTMLCopyOuter.label;"
        accesskey="&inspectorHTMLCopyOuter.accesskey;"
        oncommand="inspector.copyOuterHTML()"/>
      <menuitem id="node-menu-copyuniqueselector"
        label="&inspectorCopyUniqueSelector.label;"
        accesskey="&inspectorCopyUniqueSelector.accesskey;"
        oncommand="inspector.copyUniqueSelector()"/>
      <menuseparator/>
      <menuitem id="node-menu-delete"
        label="&inspectorHTMLDelete.label;"
        accesskey="&inspectorHTMLDelete.accesskey;"
        oncommand="inspector.deleteNode()"/>
      <menuseparator/>
      <menuitem id="node-menu-pseudo-hover"
        label=":hover" type="checkbox"
        oncommand="inspector.togglePseudoClass(':hover')"/>
      <menuitem id="node-menu-pseudo-active"
        label=":active" type="checkbox"
        oncommand="inspector.togglePseudoClass(':active')"/>
      <menuitem id="node-menu-pseudo-focus"
        label=":focus" type="checkbox"
        oncommand="inspector.togglePseudoClass(':focus')"/>
    </menupopup>
  </popupset>

我的inspectorOverlay.xul：

<?xml version="1.0" encoding="utf-8"?>
<overlay id="helloworldOverlay" xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
<popupset id="inspectorPopupSet">
<menupopup id="inspector-node-popup">
    <menuitem id="node-menu-edititem"
        label="Edit HTML"
        accesskey="E"
        oncommand="alert('hi');"/>
</menupopup>
</popupset>
</overlay>

---

样式css正在工作，这应该会在内置的inspector面板中添加一个菜单项，但看起来它什么都没有做。此覆盖是否有问题，或者对更改检查器是否有限制？

覆盖文件是

覆盖

，而不是

内容

。哎呀。

请接受此答案，以表明问题已得到回答。

<?xml version="1.0" encoding="utf-8"?>
<overlay id="helloworldOverlay" xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
<popupset id="inspectorPopupSet">
<menupopup id="inspector-node-popup">
    <menuitem id="node-menu-edititem"
        label="Edit HTML"
        accesskey="E"
        oncommand="alert('hi');"/>
</menupopup>
</popupset>
</overlay>