#go-button {
  display: none !important;
}

#urlbar + #go-button-stack #star-button {
  width: 25px;
}

#urlbar[focused="true"] + #go-button-stack #star-button {
  display: none !important;
}

#urlbar[focused="true"] + #go-button-stack #go-button {
  display: -moz-box !important;
}