[Effen] We need to update the layout manager in _syncNode() also,

sky/framework/fn.dart

Index: sky/framework/fn.dart
diff --git a/sky/framework/fn.dart b/sky/framework/fn.dart
index 43df942099d68a08d35bfa0780bb358fb63f062b..e7ff992764452bb1a800b87056b9c618b26f41c3 100644
--- a/sky/framework/fn.dart
+++ b/sky/framework/fn.dart
@@ -607,8 +607,12 @@ abstract class LayoutContainer extends Container {
     return result;
   }
 
+  // If we ever reuse sky nodes for different classes, then we should 
+  // call _root.setLayoutManager(null) during _remove() here.
+
   void _syncNode(SkyNodeWrapper old) {
     super._syncNode(old);
+    _root.setLayoutManager(() => layout(_root));
     _root.setNeedsLayout();
   }