         let navigationItems = items ?? _navigationItems
         let navigationItemView = itemContainerView ?? _navigationItemView
         
-        let _itemView = item._view
-        _itemView.translatesAutoresizingMaskIntoConstraints = false
-
-        if let _width = transition ? _widthOfTransitionNavigationItemViewForZeroContent : _widthOfNavigationItemViewForZeroContent {
+        let itemView = item._view
+        itemView.translatesAutoresizingMaskIntoConstraints = false
+
+        if let _width = _widthOfNavigationItemViewForZeroContent(transition) {
             navigationItemView.removeConstraint(_width)
         }
         
-        _itemView.removeFromSuperview()
-        navigationItemView.addSubview(_itemView)
-        
-        _itemView._button.lastBaselineAnchor.constraint(equalTo: __titleAlignmentLabel.lastBaselineAnchor).isActive = true
-        
-        _itemView.trailingAnchor.constraint(equalTo: navigationItems.last?._view.leadingAnchor ?? navigationItemView.trailingAnchor, constant: !navigationItems.isEmpty ? 0.0 : -DefaultTabNavigationItemEdgeMargin).isActive = true
-        
-        if let _leading = transition ? _leadingConstraintOfLastTransitionItemView : _leadingConstraintOfLastItemView {
-            navigationItemView.removeConstraint(_leading)
-        }
-        
-        let _leading = _itemView.leadingAnchor.constraint(equalTo: navigationItemView.leadingAnchor)
-        _leading.isActive = true
-        if transition {
-            _leadingConstraintOfLastTransitionItemView = _leading
-        } else {
-            _leadingConstraintOfLastItemView = _leading
+        itemView.removeFromSuperview()
+        navigationItemView.addSubview(itemView)
+        
+        itemView._button.lastBaselineAnchor.constraint(equalTo: __titleAlignmentLabel.lastBaselineAnchor).isActive = true
+        itemView.trailingAnchor.constraint(equalTo: navigationItems.last?._view.leadingAnchor ?? navigationItemView.trailingAnchor, constant: !navigationItems.isEmpty ? 0.0 : -DefaultTabNavigationItemEdgeMargin).isActive = true
+        
+        if let leading = _leadingConstraintOfLastItemView(transition) {
+            navigationItemView.removeConstraint(leading)
+        }
+        
+        let leading = itemView.leadingAnchor.constraint(equalTo: navigationItemView.leadingAnchor)
+            leading.isActive = true
+        if  transition { _leadingConstraintOfLastTransitionItemView = leading } else {
+            _leadingConstraintOfLastItemView = leading
         }
     }
     
     fileprivate func _createAndSetupNavigationItemViews() -> TabNavigationItemViews {
         let itemsContailerView = _createGeneralContainerView()
-        let itemsScrollView = _createGeneralScrollView(alwaysBounceHorizontal: false)
+        let itemsScrollView    = _createGeneralScrollView(alwaysBounceHorizontal: false)
         let navigationItemView = _createGeneralContainerView()
         
         _setupNavigationItemsContainerView(itemsContailerView, transition: true)

            _navigationTitleItems.append(item)
        }
        
        _calculateWidthConstantOfContentAlignmentView()
        _offsetPositionsUpToEndIndex = _calculatedPositionsUptoTitleItemAtEndIndex()
    }
    
    public func setNavigationTitleItems(_ items: [TabNavigationTitleItem], animated: Bool = false, selectedIndex index: Array<TabNavigationTitleItem>.Index = 0, actionsConfig: (() -> (ignore: Bool, actions: [TabNavigationTitleActionItem]?))? = nil, animation: ((TabNavigationTitleItemAnimationContext) -> Void)? = nil) {

    
    @objc
    fileprivate func _scrollToSelectedTitleItem(items: [TabNavigationTitleItem]? = nil, `in` scrollView: UIScrollView? = nil, animated: Bool = true) {
        let offsetx = _horizontalOffset(upto: _selectedTitleItemIndex, in: items)
        let titleItemScrollView = scrollView ?? _titleItemsScrollView
        
        // guard titleItemScrollView.contentOffset.x != offsetx else { return }
        
        if animated && titleItemScrollView === _titleItemsScrollView {
            // Remove the interactive transition delegate and animated transition delegate.
            // _delegatesQueue.remove(_interactiveTransition)
            // _delegatesQueue.remove(_animatedTransition)
            // Add did end scrolling animation call back delegate.
            // _delegatesQueue.add(_didEndScrollingAnimation)
        }
        
        if titleItemScrollView.contentOffset.x == offsetx {
            // Make sample offsets.
            titleItemScrollView.setContentOffset(CGPoint(x: offsetx - 1.0, y: 0.0), animated: false)
            // Move to the target content offset.
        };  titleItemScrollView.setContentOffset(CGPoint(x: offsetx, y: 0.0), animated: animated)
    }
    @objc
    fileprivate func _scrollToSelectedTitleItemWithAnimation() {
