@namespace url(http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul);

#performancing-sb-button {
  background-image: url("file:///C:/AllDoc/Studio17/apps/Sandbox/chrome/performancing.png") !important;
  background-position: center center !important;
  background-repeat: no-repeat !important;
}
#performancing-sb-button * {
  visibility: hidden !important;
  background-color: transparent !important;
}
#performancing-statusbar-panel *, #performancing-statusbar-panel {
  background-color: transparent !important;
}