title: Compare the listbox1 items to the listbox2 items and remove duplicates
body: <p>I'm trying to compare the listbox1 items to the listbox2 items then remove the duplicated ones.</p>
  
  <p>listbox1 contains "link1 link2 link3 link4 link5"
  'listbox1 is download items list</p>
  
  <p>listbox2 contains "link9 link5 link3"
  'listbox2 is downloaded items list</p>
  
  <p>Since "link3" and "link5" already exists in the listbox2, I want to remove them from the listbox1.</p>
  
  <p>Please help me.</p>
  
  <p>Code below doesn't work.</p>
  
  <pre><code>If listbox1.Items.Contains(listbox2.Items) Then
          listbox1.Items.Remove(listbox2.Items)
  end if
  </code></pre>