stylishEditButton.uc.js

// ==UserScript==
// @name           stylishEditButton.uc.js
// @namespace      http://d.hatena.ne.jp/Cherenkov/
// @description    http://d.hatena.ne.jp/Cherenkov/20090703/p1
// @include        chrome://browser/content/browser.xul
// ==/UserScript==

(function(){

function contextEdit(event) {
  var item = document.evaluate('//*[@class="style-menu-item"]', stylishPopup, null, 7, null);
  var btn = document.evaluate('//*[@class="stylishEditBtn"]', stylishPopup, null, 7, null);
  if(item.snapshotLength == btn.snapshotLength)
    return false;
  if(event.type == "popupshowing") {
    var style = Components.classes["@userstyles.org/style;1"]
                          .getService(Components.interfaces.stylishStyle)
                          .findForUrl(stylishCommon.cleanURI(content.document.location.href), false, 0, {});
    for(var i = 0; i < item.snapshotLength; i++) {
      var editBtn = document.createElement("menuitem");
      editBtn.setAttribute("class", "stylishEditBtn");
      editBtn.setAttribute("id", style[i].id);
      editBtn.setAttribute("label", "edit " + style[i].name);
      editBtn.addEventListener("command", function() {
        stylishCommon.openEditForId(this.id);
      }, false);
      item.snapshotItem(i).parentNode.insertBefore(editBtn, item.snapshotItem(i).nextSibling);
    }
  } else {
    for(var i = 0; i<btn.snapshotLength; i++)
      btn.snapshotItem(i).parentNode.removeChild(btn.snapshotItem(i));
  }
}

var stylishPopup = document.getElementById("stylish-popup");
stylishPopup.addEventListener("popupshowing", contextEdit, false);
stylishPopup.addEventListener("popuphiding", contextEdit, false);

})();