private static boolean isInvisibleRegionAtLineStart(@NotNull FoldRegion region) {
    if (!region.getPlaceholderText().isEmpty()) return false;
    int startOffset = region.getStartOffset();
    return startOffset == DocumentUtil.getLineStartOffset(startOffset, region.getDocument());
  }
private static boolean isInvisibleRegionAtLineStart(@NotNull FoldRegion region)