Threading and screen kind of stops and closed forms are still displaying
<p>I have multiple forms that pop up during an intensive operation. For example, when a form pops up asking the user for something, and the user clicks OK, the form's graphics stay on the main screen, even though it is closed.</p>

<p>How can I make it so that these graphics disappear completely? I'm using <code>System.Threading.Thread.sleep(10)</code> to pause the application for a bit, but the screen kind of stops and the changes are not clear. What should I do?</p>
