anchor.diff:      final BoxConstraints fullWidthConstraints = looseConstraints.tighten(width: size.width);
       Size toolBarSize = Size.zero;
   
  -    if (isChild(_Child.toolBar)) {
  -      toolBarSize = layoutChild(_Child.toolBar, fullWidthConstraints);
  -      positionChild(_Child.toolBar, Offset.zero);
  -    }
  -
  -    if (isChild(_Child.body)) {
  +    if (isChild(_ScaffoldSlot.toolBar)) {
  +      toolBarSize = layoutChild(_ScaffoldSlot.toolBar, fullWidthConstraints);
  +      positionChild(_ScaffoldSlot.toolBar, Offset.zero);
  +    }
  +
  +    if (isChild(_ScaffoldSlot.body)) {
         final double bodyHeight = size.height - toolBarSize.height;
         final BoxConstraints bodyConstraints = fullWidthConstraints.tighten(height: bodyHeight);
  -      layoutChild(_Child.body, bodyConstraints);
  -      positionChild(_Child.body, new Offset(0.0, toolBarSize.height));
  +      layoutChild(_ScaffoldSlot.body, bodyConstraints);
  +      positionChild(_ScaffoldSlot.body, new Offset(0.0, toolBarSize.height));
       }
   
       // The BottomSheet and the SnackBar are anchored to the bottom of the parent,
  
positive.code:         children: bottomSheets,
          alignment: const FractionalOffset(0.5, 1.0) // bottom-aligned, centered
        );
        _addIfNonNull(children, stack, _Child.bottomSheet);
      }
  
      if (_snackBars.isNotEmpty)
        _addIfNonNull(children, _snackBars.first._widget, _Child.snackBar);
  
      if (config.floatingActionButton != null) {
        Widget fab = new _FloatingActionButtonTransition(
          key: new ValueKey<Key>(config.floatingActionButton.key),
          child: config.floatingActionButton
        );
        children.add(new LayoutId(child: fab, id: _Child.floatingActionButton));
      }
  
      if (config.drawer != null) {
        children.add(new LayoutId(
          id: _Child.drawer,
          child: new DrawerController(
            key: _drawerKey,
            child: config.drawer
  
negative.code:     }
  
      final List<LayoutId>children = new List<LayoutId>();
      _addIfNonNull(children, materialBody, _ScaffoldSlot.body);
      _addIfNonNull(children, _modifiedToolBar, _ScaffoldSlot.toolBar);
  
      if (_currentBottomSheet != null ||
          (_dismissedBottomSheets != null && _dismissedBottomSheets.isNotEmpty)) {
  