anchor.diff:      );
   
       if (flexibleSpace == null) return appBar;
  +
       return PreferredSize(
         key: isNarrow
             ? DevToolsScaffold.narrowWidthKey
  
positive.code:             top: 4.0,
              right: animatedRightPadding,
            ),
            child: tabs,
          ),
        );
      }
  
negative.code:       );
        preferredSize = Tween<Size>(
          begin: Size.fromHeight(kToolbarHeight),
          end: Size.fromHeight(kToolbarHeight + tabBar.preferredSize.height),
        ).evaluate(appBarCurve);
        final animatedAlignment = Tween<Alignment>(
          begin: Alignment.centerRight,
          end: Alignment.bottomCenter,
        ).evaluate(appBarCurve);
  
        final rightEdge = isNarrow ? 0.0 : DevToolsScaffold.actionWidgetSize / 2;
        final animatedRightPadding = Tween<double>(
          begin: DevToolsScaffold.actionWidgetSize *
                  (widget.actions?.length ?? 0.0) +
              rightEdge,
          end: rightEdge,
        ).evaluate(appBarCurve);
  
        flexibleSpace = Align(
          alignment: animatedAlignment,
          child: Padding(
  