diff --git a/src/components/main/layout/box_builder.rs b/src/components/main/layout/box_builder.rs
index ff9457f69d4..fd5dfd5bbc1 100644
--- a/src/components/main/layout/box_builder.rs
+++ b/src/components/main/layout/box_builder.rs
@@ -356,14 +356,8 @@ impl LayoutTreeBuilder {
                               sibling_generator: Option<@mut BoxGenerator>)
                               -> Option<(@mut BoxGenerator, @mut BoxGenerator)> {
 
-        fn is_root(node: AbstractNode<LayoutView>) -> bool {
-            match node.parent_node() {
-                None => true,
-                Some(_) => false
-            }
-        }
         let display = if node.is_element() {
-            match node.style().display(is_root(node)) {
+            match node.style().display(node.is_root()) {
                 CSSDisplayNone => return None, // tree ends here if 'display: none'
                 // TODO(eatkinson) these are hacks so that the code doesn't crash
                 // when unsupported display values are used. They should be deleted
diff --git a/src/components/script/dom/node.rs b/src/components/script/dom/node.rs
index 8757f08d5d3..edd108e6881 100644
--- a/src/components/script/dom/node.rs
+++ b/src/components/script/dom/node.rs
@@ -264,6 +264,11 @@ impl<'self, View> AbstractNode<View> {
         self.with_base(|b| b.next_sibling)
     }
 
+    /// Is this node a root?
+    pub fn is_root(self) -> bool {
+        self.parent_node().is_none()
+    }
+
     //
     // Downcasting borrows
     //