gistfile1.txt

var { ActionButton } = require('sdk/ui/button/action');
var panels = require("sdk/panel");
var self = require("sdk/self");

var button = ActionButton({
  id: "my-button",
  label: "my button",
  icon: {
    "16": "./icon-16.png",
    "32": "./icon-32.png",
    "64": "./icon-64.png"
  },
  onClick: handleClick
});

var panel = panels.Panel({
  contentURL: self.data.url("panel.html"),
  position: {button}
});

function handleClick(state) {
  panel.show();
}