             constant:0)
         
         addConstraints([
-            layoutBarTop,
+            layoutBarTop!,
             layoutBarHeight,
             layoutBarLeft,
-            layoutBarRight
-            ])
+            layoutBarRight])
     }
     
     //MARK: public
     
     func mainView(view:VView)
     {
-        insertSubview(view, belowSubview:viewBar)
+        if viewBar == nil
+        {
+            addSubview(view)
+        }
+        else
+        {
+            insertSubview(view, belowSubview:viewBar!)
+        }
+        
         view.constraints(
             initialLeft:0,
             initialRight:0,

{
    static let kBarHeight:CGFloat = 64
    
    private weak var viewBar:VParentBar!
    private weak var layoutBarTop:NSLayoutConstraint!
    private let kAnimationDuration:TimeInterval = 0.3
    
    convenience init(controller:CParent)

    {
        if offsetY > 0
        {
            layoutBarTop?.constant = 0
        }
        else
        {
            layoutBarTop?.constant = offsetY
        }
    }
    
    func restartScroll()
    {
        layoutBarTop?.constant = 0
        
        UIView.animate(withDuration:kAnimationDuration)
        {
