From a98ac70b4565e729541783fbbe74924dfd50e386 Mon Sep 17 00:00:00 2001
From: Adam Barth <abarth@chromium.org>
Date: Fri, 31 Jul 2015 10:06:44 -0700
Subject: [PATCH] Stacked does not repaint when its position changes

We were marking the parent *Widget's* render object as needing layout, but
we actually need to walk up the component tree until we find the parent
*RenderObjectWrapper* so we can mark actually mark the parent render object as
needing layout.

Fixes #408
---
 packages/flutter/lib/widgets/widget.dart | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/flutter/lib/widgets/widget.dart b/packages/flutter/lib/widgets/widget.dart
index 60efa0a24b5..dcab05d7437 100644
--- a/packages/flutter/lib/widgets/widget.dart
+++ b/packages/flutter/lib/widgets/widget.dart
@@ -887,8 +887,8 @@ abstract class RenderObjectWrapper extends Widget {
     if (parentData != null) {
       assert(root.parentData != null);
       root.parentData.merge(parentData); // this will throw if the types aren't appropriate
-      if (parent.root != null)
-        parent.root.markNeedsLayout();
+      if (ancestor != null && ancestor.root != null)
+        ancestor.root.markNeedsLayout();
     }
   }