title: Firebase - building Audiences based on custom Event Parameters
body: <p>Is it possible? I can't add any custom parameter when I'm creating new Audiences at Firebase.</p>
  
  <p><a href="https://i.stack.imgur.com/87PEg.png" rel="nofollow noreferrer">Custom parameter for click_at_ad event</a></p>
  
  <p><a href="https://i.stack.imgur.com/S9veU.png" rel="nofollow noreferrer">Missing custom parameter in Audiences for click_at_ad event</a></p>