title: Firebase leaves documents greyed out on deletion. Why?
body: <p>When i delete a document containing sub collections firebase leaves the document id greyed out and It seems not deleted from the console. Tho it does not exist in snapshots. Have i deleted the data from the database wrong? (using flutter)
  <a href="https://i.stack.imgur.com/jciSO.png" rel="nofollow noreferrer">database in console</a></p>
  <p>code for deleting document but the subcollections are still there</p>
  <pre><code>Future&lt;bool&gt; deleteWorkout(String _id) async {
      try {
        await _db.collection(WORKOUTS_COLLECTION).doc(_id).delete();
        return true;
      } catch (e) {
        return false;
      }
    }
  </code></pre>