@Override
 public void onStart() {
   Timber.d(this.getClass().getSimpleName() + " onStart");
   _setupViewBindings(
       signInButton,
       errorTextView,
       myAccountDataLoginState,
       usernameField,
       passwordField,
       institutionRadio,
       userModel.getLoginStateObservable());
   super.onStart();
 }
 @Override
 public void onHiddenChanged(boolean isNowHidden) {
   if (isNowHidden) {
     Timber.d(this.getClass().getSimpleName() + " isNowHidden");
     _teardownViewBindings(signInButton);
   } else {
     Timber.d(this.getClass().getSimpleName() + " isNowVisible");
     _setupViewBindings(
         signInButton,
         errorTextView,
         myAccountDataLoginState,
         usernameField,
         passwordField,
         institutionRadio,
         userModel.getLoginStateObservable());
   }
   super.onHiddenChanged(isNowHidden);
 }