             let attributes = layoutAttributesInAttachmentBehaviorForId(id)!
             dynamicAnimator.removeBehavior(behavior)
             gravityBehavior.removeItem(attributes)
-            collisionBehavior.removeItem(attributes)
+//            collisionBehavior.removeItem(attributes)
             
             attachmentBehaviors[id] = nil
         }

    func layoutAttributesInAttachmentBehaviorForId(id : Int) -> NewtownianLayoutAttributes? {
        let behavior = attachmentBehaviors[id]
        return (behavior?.items.first as? NewtownianLayoutAttributes)
    }
    
    override func prepareLayout() {

            attachmentBehavior.frequency = 1.0
            
            attachmentBehaviors[id] = attachmentBehavior
            
            print("---------------------")
            for behavior in dynamicAnimator.behaviors {
                printBehaviorHierachy(behavior, indent: "==>")
            }
            
            dynamicAnimator.addBehavior(attachmentBehavior)

            gravityBehavior.addItem(attributes)
//            collisionBehavior.addItem(attributes)
        }
        
        if change {
