I have a calculator app with lots of buttons. Some of the buttons change appearance when pressed. Others do not. Some of those that do not change the state of a display text field and others do not. The display change is that the button goes white when pressed. I have no explicit code to make a change in appearance in any of the buttons. The display consists of a TextField followed by 4 rows of 6 buttons followed by 4 rows of 6 buttons. What is the explanation for this behavior.
