title: How does IntelliJ's "Reimport All Maven Projects" button work?
body: <p>How does IntelliJ's "Reimport All Maven Projects" button actually work?</p>
  
  <p>I'm asking this because I see that IntelliJ's reimport button's behavior is <strong>different</strong> than that of running the <code>mvn</code> command with the <code>-U</code> argument, and it's not clear to me why.</p>