Program: 60795
Project: 60795
Buggy source:
@Override protected void populateItem(final ListItem<ConnConfProperty> item){
  final ConnConfProperty property=item.getModelObject();
  final Label label=new Label("String_Node_Str",property.getSchema().getDisplayName() == null || property.getSchema().getDisplayName().isEmpty() ? property.getSchema().getName() : property.getSchema().getDisplayName());
  item.add(label);
  final FieldPanel field;
  if (GUARDED_STRING.equals(property.getSchema().getType())) {
    field=new AjaxPasswordFieldPanel("String_Node_Str",label.getDefaultModelObjectAsString(),new PropertyModel<String>(property,"String_Node_Str"),true).setRequired(property.getSchema().isRequired()).setTitle(property.getSchema().getHelpMessage());
  }
 else {
    field=new AjaxTextFieldPanel("String_Node_Str",label.getDefaultModelObjectAsString(),new PropertyModel<String>(property,"String_Node_Str"),true).setRequired(property.getSchema().isRequired()).setTitle(property.getSchema().getHelpMessage());
    if (property.getSchema().isRequired()) {
      field.addRequiredLabel();
    }
  }
  item.add(field);
  final AjaxDropDownChoicePanel<Boolean> overridable=new AjaxDropDownChoicePanel<Boolean>("String_Node_Str","String_Node_Str",new PropertyModel(property,"String_Node_Str"),false);
  overridable.setChoiceRenderer(new OverridableRenderer());
  overridable.setChoices(Arrays.asList(new Boolean[]{ConnParameterType.NOT_OVERRIDABLE.getOverridable(),ConnParameterType.OVERRIDABLE.getOverridable()}));
  overridable.setStyleShet("String_Node_Str");
  overridable.addRequiredLabel();
  item.add(overridable);
  connectorTO.getConfiguration().add(property);
}

Fixed version (ground truth):
@Override protected void populateItem(final ListItem<ConnConfProperty> item){
  final ConnConfProperty property=item.getModelObject();
  final Label label=new Label("String_Node_Str",property.getSchema().getDisplayName() == null || property.getSchema().getDisplayName().isEmpty() ? property.getSchema().getName() : property.getSchema().getDisplayName());
  item.add(label);
  final FieldPanel field;
  if (GUARDED_STRING.equals(property.getSchema().getType())) {
    field=new AjaxPasswordFieldPanel("String_Node_Str",label.getDefaultModelObjectAsString(),new PropertyModel<String>(property,"String_Node_Str"),true).setRequired(property.getSchema().isRequired()).setTitle(property.getSchema().getHelpMessage());
  }
 else {
    field=new AjaxTextFieldPanel("String_Node_Str",label.getDefaultModelObjectAsString(),new PropertyModel<String>(property,"String_Node_Str"),true).setRequired(property.getSchema().isRequired()).setTitle(property.getSchema().getHelpMessage());
    if (property.getSchema().isRequired()) {
      field.addRequiredLabel();
    }
  }
  item.add(field);
  final AjaxDropDownChoicePanel<Boolean> overridable=new AjaxDropDownChoicePanel<Boolean>("String_Node_Str","String_Node_Str",new PropertyModel(property,"String_Node_Str"),false);
  overridable.setChoiceRenderer(new OverridableRenderer());
  overridable.setChoices(Arrays.asList(new Boolean[]{ConnParameterType.NOT_OVERRIDABLE.getOverridable(),ConnParameterType.OVERRIDABLE.getOverridable()}));
  overridable.setStyleShet("String_Node_Str" + "String_Node_Str");
  overridable.addRequiredLabel();
  item.add(overridable);
  connectorTO.getConfiguration().add(property);
}