@Nullable
    private VirtualFile getContentFile(@NotNull Side side) {
      DiffContent content = side.select(myRequest.getContents());
      VirtualFile file = content instanceof FileContent ? ((FileContent)content).getFile() : null;
      return file != null && file.isValid() ? file : null;
    }
@Nullable
    private VirtualFile getContentFile(@NotNull Side side)