From d7576d223dc87155e2df29767444f7cf5fe6bbe4 Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Wed, 3 Feb 2016 15:34:20 +0000
Subject: [PATCH 1/2] Don't try to use local echoes as scroll tokens

Local echoes don't have a (usable) event id, so don't use them when remembering
the scroll state of a room.
---
 src/components/structures/RoomView.js | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/components/structures/RoomView.js b/src/components/structures/RoomView.js
index c46149bfeb..09b6baf2be 100644
--- a/src/components/structures/RoomView.js
+++ b/src/components/structures/RoomView.js
@@ -995,8 +995,18 @@ module.exports = React.createClass({
 
             var eventId = mxEv.getId();
             var highlight = (eventId == this.props.highlightedEventId);
+
+            var scrollToken = eventId;
+            // we can't use local echoes as scroll tokens, because their event
+            // IDs change.
+            if (mxEv.status) {
+                scrollToken = undefined;
+            }
+
             ret.push(
-                <li key={eventId} ref={this._collectEventNode.bind(this, eventId)} data-scroll-token={eventId}>
+                <li key={eventId} 
+                        ref={this._collectEventNode.bind(this, eventId)} 
+                        data-scroll-token={scrollToken}>
                     <EventTile mxEvent={mxEv} continuation={continuation}
                         last={last} isSelectedEvent={highlight}/>
                 </li>

From 8f5c73988649d8251dba5cde3c8d8150f1b10b4c Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <github@rvanderhoff.org.uk>
Date: Thu, 4 Feb 2016 14:05:16 +0000
Subject: [PATCH 2/2] Clean up scrollToken assignment

---
 src/components/structures/RoomView.js | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/src/components/structures/RoomView.js b/src/components/structures/RoomView.js
index 09b6baf2be..6e9835834a 100644
--- a/src/components/structures/RoomView.js
+++ b/src/components/structures/RoomView.js
@@ -996,12 +996,9 @@ module.exports = React.createClass({
             var eventId = mxEv.getId();
             var highlight = (eventId == this.props.highlightedEventId);
 
-            var scrollToken = eventId;
-            // we can't use local echoes as scroll tokens, because their event
-            // IDs change.
-            if (mxEv.status) {
-                scrollToken = undefined;
-            }
+            // we can't use local echoes as scroll tokens, because their event IDs change.
+            // Local echos have a send "status".
+            var scrollToken = mxEv.status ? undefined : eventId;
 
             ret.push(
                 <li key={eventId}