anchor.diff:          if omnipresent then
               tree.OmnipresentElements.Add element |> ignore
           else
  -            if not (SpatialNode.intersectingBounds bounds tree.Node) then
  +            if not (SpatialNode.isIntersectingBounds bounds tree.Node) then
                   Log.info "Element is outside spatial tree's containment area or is being added redundantly."
                   tree.OmnipresentElements.Add element |> ignore
               else SpatialNode.addElement bounds element tree.Node
  
positive.code:         match node.Children with
          | Left nodes ->
              for node in nodes do
                  if intersectingBounds oldBounds node || intersectingBounds newBounds node then
                      updateElement oldBounds newBounds element node
          | Right elements ->
              if intersectingBounds oldBounds node then
                  if not (intersectingBounds newBounds node) then elements.Remove element |> ignore
              elif intersectingBounds newBounds node then
                  elements.Add element |> ignore
  
      let rec internal getElementsAtPoint point node (set : 'e HashSet) =
  
negative.code:         if omnipresent then 
              tree.OmnipresentElements.Remove element |> ignore
          else
              if not (SpatialNode.isIntersectingBounds bounds tree.Node) then
                  Log.info "Element is outside spatial tree's containment area or is not present for removal."
                  tree.OmnipresentElements.Remove element |> ignore
              else SpatialNode.removeElement bounds element tree.Node
  
      let updateElement oldBounds newBounds element tree =
          let oldInBounds = SpatialNode.isIntersectingBounds oldBounds tree.Node
          let newInBounds = SpatialNode.isIntersectingBounds newBounds tree.Node
          if oldInBounds && not newInBounds then
              // going out of bounds
              Log.info "Element is outside spatial tree's containment area."
  