diff --git a/lib/hooks/search-threads.js b/lib/hooks/search-threads.js
--- a/lib/hooks/search-threads.js
+++ b/lib/hooks/search-threads.js
@@ -1,5 +1,6 @@
 // @flow
 
+import _orderBy from 'lodash/fp/orderBy.js';
 import * as React from 'react';
 
 import { useSidebarInfos } from './sidebar-hooks.js';
@@ -99,6 +100,7 @@
 }
 
 const emptyArray: $ReadOnlyArray<SidebarInfo> = [];
+const sortFunc = _orderBy('lastUpdatedTime')('desc');
 
 function useSearchSidebars(
   threadInfo: ThreadInfo,
@@ -167,7 +169,12 @@
     })();
   }, [childThreadInfos, initialSidebarItems]);
 
-  return useSearchThreads(threadInfo, sidebarItems);
+  const sortedSidebarItems = React.useMemo(
+    () => sortFunc(sidebarItems),
+    [sidebarItems],
+  );
+
+  return useSearchThreads(threadInfo, sortedSidebarItems);
 }
 
 function useSearchSubchannels(
diff --git a/lib/hooks/sidebar-hooks.js b/lib/hooks/sidebar-hooks.js
--- a/lib/hooks/sidebar-hooks.js
+++ b/lib/hooks/sidebar-hooks.js
@@ -44,7 +44,9 @@
           mostRecentNonLocalMessage,
         });
       }
-      result[parentID] = _orderBy('lastUpdatedTime')('desc')(sidebarInfos);
+      result[parentID] = _orderBy('lastUpdatedAtLeastTime')('desc')(
+        sidebarInfos,
+      );
     }
     return result;
   }, [childThreadInfoByParentID, messageStore, getLastUpdatedTimes]);
diff --git a/lib/selectors/chat-selectors.js b/lib/selectors/chat-selectors.js
--- a/lib/selectors/chat-selectors.js
+++ b/lib/selectors/chat-selectors.js
@@ -115,12 +115,13 @@
           : lastUpdatedAtLeastTime;
 
       const lastUpdatedTimeIncludingSidebars = (async () => {
-        if (sidebars.length === 0) {
-          return await lastUpdatedTime;
-        }
-        const [lastUpdatedTimeResult, sidebarLastUpdatedTimeResult] =
-          await Promise.all([lastUpdatedTime, sidebars[0].lastUpdatedTime]);
-        return Math.max(lastUpdatedTimeResult, sidebarLastUpdatedTimeResult);
+        const lastUpdatedTimePromises = [
+          lastUpdatedTime,
+          ...sidebars.map(sidebar => sidebar.lastUpdatedTime),
+        ];
+        const lastUpdatedTimes = await Promise.all(lastUpdatedTimePromises);
+        const max = lastUpdatedTimes.reduce((a, b) => Math.max(a, b), -1);
+        return max;
       })();
 
       const allInitialSidebarItems = getAllInitialSidebarItems(sidebars);
diff --git a/lib/shared/sidebar-item-utils.js b/lib/shared/sidebar-item-utils.js
--- a/lib/shared/sidebar-item-utils.js
+++ b/lib/shared/sidebar-item-utils.js
@@ -1,5 +1,7 @@
 // @flow
 
+import _orderBy from 'lodash/fp/orderBy.js';
+
 import type { ThreadInfo } from '../types/minimally-encoded-thread-permissions-types.js';
 import {
   maxReadSidebars,
@@ -22,17 +24,21 @@
     }
   | { +type: 'spacer' };
 
+const sortFunc = _orderBy('lastUpdatedTime')('desc');
+
 function getSidebarItems(
   allSidebarItems: $ReadOnlyArray<SidebarThreadItem>,
 ): SidebarItem[] {
-  const numUnreadSidebars = allSidebarItems.filter(
+  const sorted = sortFunc(allSidebarItems);
+
+  const numUnreadSidebars = sorted.filter(
     sidebar => sidebar.threadInfo.currentUser.unread,
   ).length;
   let numReadSidebarsToShow = maxReadSidebars - numUnreadSidebars;
   const threeDaysAgo = Date.now() - threeDays;
 
   const sidebarItems: SidebarItem[] = [];
-  for (const sidebar of allSidebarItems) {
+  for (const sidebar of sorted) {
     if (sidebarItems.length >= maxUnreadSidebars) {
       break;
     } else if (sidebar.threadInfo.currentUser.unread) {
@@ -46,14 +52,14 @@
     }
   }
 
-  const numReadButRecentSidebars = allSidebarItems.filter(
+  const numReadButRecentSidebars = sorted.filter(
     sidebar =>
       !sidebar.threadInfo.currentUser.unread &&
       sidebar.lastUpdatedTime > threeDaysAgo,
   ).length;
   if (
     sidebarItems.length < numUnreadSidebars + numReadButRecentSidebars ||
-    (sidebarItems.length < allSidebarItems.length && sidebarItems.length > 0)
+    (sidebarItems.length < sorted.length && sidebarItems.length > 0)
   ) {
     sidebarItems.push({
       type: 'seeMore',