@Override
  public @Nullable String getCustomizationAt(@NotNull Editor editor, @NotNull Point location) {
    FoldRegion region = ((FoldingModelEx)editor.getFoldingModel()).getFoldingPlaceholderAt(location);
    return region instanceof CustomFoldRegion
           ? location.x < 20 ? DefaultLanguageHighlighterColors.DOC_COMMENT_GUIDE.getExternalName()
                             : DefaultLanguageHighlighterColors.DOC_COMMENT_LINK.getExternalName()
           : null;
  }
@Override
  public @Nullable String getCustomizationAt(@NotNull Editor editor, @NotNull Point location)