     
     private var openFolderCollectionView: SwiftBoardCollectionView?
     private var dragProxyState: DragProxyState?
+    private var dragProxyReturnToRect: CGRect?
     private var currentDragState: DragState?
     private var currentDropState: DropState?
     

    private func endDrag() {
        if let dragState = currentDragState {
            let proxyState = dragProxyState!
            let cell = dragState.cell
            let collectionView = self
            
            UIView.animateWithDuration(0.2, animations: { () -> Void in
                proxyState.view.transform = CGAffineTransformIdentity
                proxyState.view.alpha = 1
                proxyState.view.frame = collectionView.convertRect(cell.frame, fromView: cell.superview)
            }, completion: { (Bool) -> Void in
                dragState.itemViewModel.dragging = false
                
                proxyState.view.removeFromSuperview()
                self.currentDragState = nil
                self.currentDropState = nil
            })
        }
    }
    

                        if let folderCell = dropState.cell as? FolderCollectionViewCell {
                            let newIndexPath = NSIndexPath(forItem: newIndex, inSection: 0)
                            if let newAppCell = folderCell.collectionView.cellForItemAtIndexPath(newIndexPath) {
                                dragProxyReturnToRect = convertRect(newAppCell.frame, fromView: newAppCell.superview)
                                endDrag()
                            }
                        }
                    }
