@NotNull
  public static JComponent createComponent(@Nullable String fileName, @Nullable DiffContext context) {
    String message = DiffBundle.message("error.cant.show.diff.for.unknown.file");
    if (fileName == null) return DiffUtil.createMessagePanel(message);
    return ErrorDiffTool.createReloadMessagePanel(context, message, DiffBundle.message("button.associate.file.type"),
                                                  () -> FileTypeChooser.associateFileType(fileName));
  }
@NotNull
  public static JComponent createComponent(@Nullable String fileName, @Nullable DiffContext context)