+ PaintState GetPaintState();
+
+ /**
+ * Inserts the actor to the button.
+ */
+ void InsertChild( unsigned int index, Actor& actor );
+
+ /**
+ * Removes the actor from the button.
+ */
+ void RemoveChild( Actor& actor );
+
+ /**
+ * Finds the index of the actor.
+ * If the actor doesn't exist, return the last index + 1.
+ */
+ unsigned int FindChildIndex( Actor& actor );