diff --git a/button.go b/button.go
index e9b02b7..2aec8c0 100644
--- a/button.go
+++ b/button.go
@@ -69,6 +69,7 @@ func (this *Button) SetIcon (id tomo.Icon) {
 	if this.icon != nil {
 		this.Insert(this.icon, this.label)
 	}
+	this.SetTag("icon", this.icon != nil)
 	this.applyLayout()
 }