     lazy var dynamicAnimator : UIDynamicAnimator = { [unowned self] in
         let result = UIDynamicAnimator(collectionViewLayout: (self as UICollectionViewFlowLayout))
         result.addBehavior(self.gravityBehavior)
-        result.addBehavior(self.collisionBehavior)
+//        result.addBehavior(self.collisionBehavior)
         return result
     }()
     

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

            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 {
