private @Nullable DropDownLink<String> createChangedLinesDropDownLink() {
    if (!VcsFacade.getInstance().hasActiveVcss(getProject())) return null;

    String wholeFile = CodeInsightBundle.message("actions.on.save.page.label.whole.file");
    String changedLines = CodeInsightBundle.message("actions.on.save.page.label.changed.lines");

    String current = isFormatOnlyChangedLines() ? changedLines : wholeFile;

    return new DropDownLink<>(current, List.of(wholeFile, changedLines),
                              choice -> setFormatOnlyChangedLines(Strings.areSameInstance(choice, changedLines)));
  }
private @Nullable DropDownLink<String> createChangedLinesDropDownLink()