private @Nullable String getDescriptorText(final @Nullable StringDescriptor titleDescriptor) {
    if (titleDescriptor == null) return null;
    final String value = titleDescriptor.getValue();
    if (value == null) { // from res bundle
      final String resolvedValue = StringDescriptorManager.getInstance(getModule()).resolve(this, titleDescriptor);
      titleDescriptor.setResolvedValue(resolvedValue);
      return resolvedValue;
    }
    return value;
  }
private @Nullable String getDescriptorText(final @Nullable StringDescriptor titleDescriptor)