diff --git a/progress.go b/progress.go
index c50c6e0..0ad7dc4 100644
--- a/progress.go
+++ b/progress.go
@@ -213,6 +213,7 @@
 			case SortBottom:
 				sort.Sort(SortableBarSlice(bars))
 			}
+			// TODO: pipelines?
 			for _, b := range bars {
 				buf := b.Bytes(width)
 				buf = append(buf, '\n')