     
     // MARK: - Helpers
     
+    private func refreshToolbarItems() {
+        var toolbarItems = [UIBarButtonItem]()
+        
+        let flexibleSpaceItem = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
+        let fixedSpaceItem = UIBarButtonItem(barButtonSystemItem: .fixedSpace, target: nil, action: nil)
+        fixedSpaceItem.width = 18
+
+        if isEditing {
+            trashButtonItem.isEnabled = false
+            actionButtonItem.isEnabled = false
+            
+            toolbarItems = [editButtonItem, flexibleSpaceItem, trashButtonItem, fixedSpaceItem, actionButtonItem]
+        }
+        else {
+            toolbarItems = [editButtonItem, flexibleSpaceItem, addButtonItem]
+        }
+        
+        self.toolbarItems = toolbarItems
+    }
+    
     private func startNewDoodle() {
         setEditing(false, animated: true)
         

        
        view.addSubview(collectionView)                
        view.addConstraints(NSLayoutConstraint.constraints(forPinningViewToSuperview: collectionView))
    }
    
    override func viewWillAppear(_ animated: Bool) {

                collectionView.insertItems(at: [IndexPath(item: 0, section: 0)])
            }
        }
        else if doodles.count == 0 && collectionView.numberOfSections > 0 {
            collectionView.deleteSections(IndexSet([0]))
        }
        else if doodles.count < prevDoodles.count {
