title: Chrome extension: How to detect if a different chrome extension is open?
body: <p>In my chrome extension, I want to detect when another chrome extensions pop up window is open. Let's say my extension is named A and there is another chrome extension named B. I want code to execute on A when B is opened.</p>
  <p>Is it also possible for A to interact with B's popup menu? As in A detects that B is open, so it will fill in input forms and click buttons?</p>