         return transitionView
     }()
     
+    open var isTransitioning = false {
+        didSet {
+            headerTransitionView.isHidden = !isTransitioning
+        }
+    }
+    
     internal let supplementaryContainerView = SupplementaryView()
     
     open var isStretchy = true {

            revealingGapHeight = minimumCollapseOffset
            break
        case .refresh:
            break
        }
        

            
            parallaxHeaderContainerView.center = CGPoint(x: parallaxHeaderContainerView.frame.midX, y: revealingGapHeight + gap - parallaxHeaderContainerView.frame.height / 2)
            
            headerTransitionView.frame = parallaxHeaderContainerView.frame
            
            setPageTabBarViewPosition()
            
        } else {
