anchor.diff:  
                   filtered
                   |> Seq.map @~ fun (track, httpref) ->
  -                    activeTrackWidget track httpref
  +                    trackListingWidget track httpref
                       |> fun x -> x :> Doc
                   |> fun divs ->
                       div divs
  
positive.code:             ]
          ]
  
      let library tracks =
          //JS.Alert("blah")
          //div [text @~ sprintf "%A" tracks]
  
negative.code:             //let t = [0..3] |> Seq.ofList
              //let t = tracks
              div [
                  client <@ Client.playerWidget () @>
                  client <@ Client.library t @>
              ]
          )
  