title: Popover window in Electron
body: <p>Is there a way to have a popover window that goes beyond the boundary of the main window? Doesn't have to be a child window. But would be great if it's attached to the main window. I know there's modal window option, but that's not exactly the look I'm aiming for. </p>
  
  <p>Example of popover window:</p>
  
  <p><a href="https://i.stack.imgur.com/u9YCj.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/u9YCj.png" alt="Example of popover window"></a></p>
  
  <p>Any tricks to achieve something like this in Electron? 
  Thanks!</p>
  
  <p>(I'm building this in React, if that's good to note)</p>