Make a button appear but only after the slide has been viewed the first time around. My students are going to revisit notes taken earlier in the lesson. I want them to be able to get back to where they left off by using a button. However, the button cannot be in the lesson the first time the user visits the slide it would only confuse them. So I need the button to display after they've view the slide and want to revisit the slide for the second time.