From 7429b7dcd9ef3a2b21013bd394fc369c654efbd4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mateusz=20Na=C5=9Bciszewski?= <matin1111@wp.pl>
Date: Thu, 14 Sep 2017 12:24:03 +0200
Subject: [PATCH] Avoid creating multiple scroll roots for sticky tables

This should prevent problems when a table has position:sticky and
overflow:scroll.
---
 components/layout/display_list_builder.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/components/layout/display_list_builder.rs b/components/layout/display_list_builder.rs
index 187799e6f76..074fe441010 100644
--- a/components/layout/display_list_builder.rs
+++ b/components/layout/display_list_builder.rs
@@ -2648,6 +2648,9 @@ impl BlockFlowDisplayListBuilding for BlockFlow {
 
         let new_clip_scroll_node_id = ClipId::new(self.fragment.unique_id(IdType::OverflowClip),
                                                   state.pipeline_id.to_webrender());
+        if state.has_clip_scroll_node(new_clip_scroll_node_id) {
+             return;
+        }
         let parent_id = self.clip_and_scroll_info(state.pipeline_id).scroll_node_id;
         state.add_clip_scroll_node(
             ClipScrollNode {