anchor.diff:      // ===================================================================================
       type PointCloudInfo =
           {
  +            /// the element-types for all available attributes
               attributeTypes : Map<Symbol, Type>
   
               /// the target point distance in pixels
  
positive.code:             let activate (n : GeometryRef) =
                  let size = n.range.Size
                  if inactive.Remove n then
                      Interlocked.Add(&inactiveSize, -size) |> ignore
  
                  Interlocked.Add(&activeSize, size) |> ignore
                  levelCounts.[n.node.level] <- levelCounts.[n.node.level] + 1
  
  
  
negative.code:                         false
                  )
  
                  // return the resulting node-set
                  result :> ISet<_>
  
  
  
  