title: Slickgrid: aggregate at grouping row header
body: <p>I'm trying to display the aggregates of sum at the same grouping row. Since I'm working with at least four group levels, the aggregate at the end seems a bit confusing (can be hard to distinguish), as you can see here in grey color.</p>
  <p><a href="https://i.stack.imgur.com/CmGa2.png" rel="nofollow noreferrer">Image example</a></p>
  <p>I'm kinda newbie at all, so I'm stuck at what I can really do. Tried to replicate the type of Aggregate inside the formatter string, but it turns out a [Object].
  I've found some few old topics with similar subject, but didn't work to me yet.</p>
  <p>Thx</p>