diff --git a/io/input/router.go b/io/input/router.go
index accb37ff..de6efa34 100644
--- a/io/input/router.go
+++ b/io/input/router.go
@@ -60,7 +60,7 @@ type Router struct {
 }
 
 // Source implements the interface between a Router and user interface widgets.
-// The value Source is disabled.
+// The zero-value Source is disabled.
 type Source struct {
 	r *Router
 }