推荐脚本better addon-bar, 只显示扩展栏中的状态栏,并且自动隐藏

#addon-bar {
  position: fixed;
  bottom: -22px;
  right: 1px;
  border: 0 !important;
  -moz-appearance: none !important;
  -moz-transition: bottom .5s 1s ease-in;
  padding-top: 22px !important;
}

#browser-bottombox {
  position: fixed;
}

#addon-bar:hover {
 bottom: 0;
 -moz-transition: bottom .5s .4s ease-out;
}

#main-window[sizemode="maximized"] #addon-bar {
  right: 0;
}

#addon-bar > #status-bar {
  margin: 0 !important;
  padding: 0 2px 0 2px;
  border-radius: 4px 0 0 0;
  border: 0 !important;
  border-left: 1px solid rgba(0,0,0,.25) !important;
  border-top: 1px solid rgba(0,0,0,.25) !important;
  background-color: rgb(207, 219, 236) !important;
  background-image: -moz-linear-gradient(rgba(255,255,255,.5), rgb(207,220,236)) !important;
  box-shadow: 0 0 0 1px rgba(255,255,255,.5) inset;
}