title: Jenkins: GitHub hook trigger for GITScm polling
body: <p>I try to configure Jenkins. I want a simple behavior: trigger a build on new pull request.</p>
  
  <p>So, I created a job and configured it, but I checked the checkbox for:
  <a href="https://i.stack.imgur.com/QFrZk.png" rel="noreferrer"><img src="https://i.stack.imgur.com/QFrZk.png" alt="enter image description here"></a></p>
  
  <p>And as you can see nothing is dropped down.</p>
  
  <p>If I click the question mark on the right side, I see:</p>
  
  <blockquote>
    <p>If jenkins will receive PUSH GitHub hook from repo defined in Git SCM
    section it will trigger Git SCM polling logic. So polling logic in
    fact belongs to Git SCM.</p>
  </blockquote>
  
  <p>But where is the "Git SCM section"?</p>