@Override
    public boolean canClose(final String inputString) {
      final String newPropertyName = myPrefix == null ? inputString : (myPrefix + mySeparator + inputString);

      final ResourceBundle resourceBundle = myResourceBundleEditor.getResourceBundle();
      for (final PropertiesFile propertiesFile : resourceBundle.getPropertiesFiles()) {
        IProperty key = propertiesFile.findPropertyByKey(newPropertyName);
        if (key != null) {
          Messages.showErrorDialog(ResourceBundleEditorBundle.message("already.exists.warning.message", newPropertyName),
                                   ResourceBundleEditorBundle.message("new.property.action.text"));
          return false;
        }
      }

      return true;
    }
@Override
    public boolean canClose(final String inputString)