diff --git a/progress.go b/progress.go
index a93f964..e7dc45f 100644
--- a/progress.go
+++ b/progress.go
@@ -380,6 +380,7 @@
 	}
 
 	switch len(pool) {
+	case 0:
 	case 1:
 		heap.Push(&s.bHeap, pool[0])
 	default: