From dedaf0f5a2288705673a6cf70dd577519f37d8f3 Mon Sep 17 00:00:00 2001
From: Bruno Windels <brunow@matrix.org>
Date: Fri, 15 Feb 2019 12:36:54 +0100
Subject: [PATCH] disable lazy list rendering if extraTiles are provided

---
 src/components/structures/RoomSubList.js | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/src/components/structures/RoomSubList.js b/src/components/structures/RoomSubList.js
index f7f74da728..d72f84b47f 100644
--- a/src/components/structures/RoomSubList.js
+++ b/src/components/structures/RoomSubList.js
@@ -282,7 +282,7 @@ const RoomSubList = React.createClass({
         this.setState({scrollTop: this.refs.scroller.getScrollTop()});
     },
 
-    _getRenderItems: function() {
+    _getList: function() {
         // try our best to not create a new array
         // because LazyRenderList rerender when the items prop
         // is not the same object as the previous value
@@ -296,6 +296,12 @@ const RoomSubList = React.createClass({
         return list.concat(extraTiles);
     },
 
+    _canUseLazyListRendering() {
+        // for now disable lazy rendering as they are already rendered tiles
+        // not rooms like props.list we pass to LazyRenderList
+        return !this.props.extraTiles || !this.props.extraTiles.length;
+    },
+
     render: function() {
         const len = this.props.list.length + this.props.extraTiles.length;
         const isCollapsed = this.state.hidden && !this.props.forceExpand;
@@ -310,7 +316,7 @@ const RoomSubList = React.createClass({
                 return <div ref="subList" className={subListClasses}>
                     {this._getHeaderJsx(isCollapsed)}
                 </div>;
-            } else {
+            } else if (this._canUseLazyListRendering()) {
                 return <div ref="subList" className={subListClasses}>
                     {this._getHeaderJsx(isCollapsed)}
                     <IndicatorScrollbar ref="scroller" className="mx_RoomSubList_scroll" onScroll={ this._onScroll }>
@@ -319,7 +325,16 @@ const RoomSubList = React.createClass({
                             height={ this.state.scrollerHeight }
                             renderItem={ this.makeRoomTile }
                             itemHeight={34}
-                            items={this._getRenderItems()} />
+                            items={ this.props.list } />
+                    </IndicatorScrollbar>
+                </div>;
+            } else {
+                const roomTiles = this.props.list.map(r => this.makeRoomTile(r));
+                const tiles = roomTiles.concat(this.props.extraTiles);
+                return <div ref="subList" className={subListClasses}>
+                    {this._getHeaderJsx(isCollapsed)}
+                    <IndicatorScrollbar ref="scroller" className="mx_RoomSubList_scroll" onScroll={ this._onScroll }>
+                        { tiles }
                     </IndicatorScrollbar>
                 </div>;
             }