@Nullable
  @Override
  public VirtualFile getBaseDirectory() {
    VirtualFile baseDir = null;
    for (PropertiesFile file : myFiles) {
      final VirtualFile currentBaseDir = file.getContainingFile().getVirtualFile().getParent();
      if (baseDir == null) {
        baseDir = currentBaseDir;
      } else if (!baseDir.equals(currentBaseDir)) {
        return null;
      }
    }
    return baseDir;
  }
@Nullable
  @Override
  public VirtualFile getBaseDirectory()