diff --git a/bar_filler_bar.go b/bar_filler_bar.go
index b63e5e1..0fe19c0 100644
--- a/bar_filler_bar.go
+++ b/bar_filler_bar.go
@@ -67,7 +67,7 @@
 
 func (s *barFiller) SetStyle(style string) {
 	if !utf8.ValidString(style) {
-		return
+		panic("invalid bar style")
 	}
 	if style == "" {
 		style = DefaultBarStyle