title: Can Chrome extension content scripts access window.opener?
body: <p>In my extension, I'm trying to determine whether a new tab was created as a popup by another tab and if so, which tab.</p>
  
  <p>I thought I would be able to use window.opener from a content script to help figure this out. But it looks like window.opener doesn't work correctly in content scripts.</p>
  
  <p>When I create a tab manually, it's window.opener is null as expected.</p>
  
  <p>When a tab is created as a popup by another tab, its window.opener is undefined. I can infer from this that the tab was created as a popup, but I can't use it to figure out which tab created the new one.</p>
  
  <p>Is this a known issue, and does anybody know of any workarounds?</p>