diff --git a/lib/hooks/thread-time.js b/lib/hooks/thread-time.js
new file mode 100644
index 000000000..1bb46590d
--- /dev/null
+++ b/lib/hooks/thread-time.js
@@ -0,0 +1,25 @@
+// @flow
+
+import type { MessageInfo, MessageStore } from '../types/message-types.js';
+import type { ThreadInfo } from '../types/minimally-encoded-thread-permissions-types.js';
+
+function getLastUpdatedTime(
+  threadInfo: ThreadInfo,
+  messageStore: MessageStore,
+  messages: { +[id: string]: ?MessageInfo },
+): number {
+  const thread = messageStore.threads[threadInfo.id];
+  if (!thread) {
+    return threadInfo.creationTime;
+  }
+  for (const messageID of thread.messageIDs) {
+    const messageInfo = messages[messageID];
+    if (!messageInfo) {
+      continue;
+    }
+    return messageInfo.time;
+  }
+  return threadInfo.creationTime;
+}
+
+export { getLastUpdatedTime };
diff --git a/lib/selectors/chat-selectors.js b/lib/selectors/chat-selectors.js
index 120b05a51..dc6f9787d 100644
--- a/lib/selectors/chat-selectors.js
+++ b/lib/selectors/chat-selectors.js
@@ -1,683 +1,665 @@
 // @flow
 
 import invariant from 'invariant';
 import _filter from 'lodash/fp/filter.js';
 import _flow from 'lodash/fp/flow.js';
 import _map from 'lodash/fp/map.js';
 import _orderBy from 'lodash/fp/orderBy.js';
 import * as React from 'react';
 import { createSelector } from 'reselect';
 import { createObjectSelector } from 'reselect-map';
 
 import {
   threadInfoFromSourceMessageIDSelector,
   threadInfoSelector,
 } from './thread-selectors.js';
 import { useSidebarInfos } from '../hooks/sidebar-hooks.js';
+import { getLastUpdatedTime } from '../hooks/thread-time.js';
 import {
   createMessageInfo,
   getMostRecentNonLocalMessageID,
   messageKey,
   robotextForMessageInfo,
   sortMessageInfoList,
 } from '../shared/message-utils.js';
 import { messageSpecs } from '../shared/messages/message-specs.js';
 import { threadInChatList, threadIsPending } from '../shared/thread-utils.js';
 import { messageTypes } from '../types/message-types-enum.js';
 import {
   type ComposableMessageInfo,
   isComposableMessageType,
   type LocalMessageInfo,
   type MessageInfo,
   type MessageStore,
   type RobotextMessageInfo,
 } from '../types/message-types.js';
 import type {
   ThreadInfo,
   RawThreadInfo,
 } from '../types/minimally-encoded-thread-permissions-types.js';
 import type { BaseAppState } from '../types/redux-types.js';
 import { threadTypeIsSidebar } from '../types/thread-types-enum.js';
 import {
   maxReadSidebars,
   maxUnreadSidebars,
   type SidebarInfo,
 } from '../types/thread-types.js';
 import type {
   AccountUserInfo,
   RelativeUserInfo,
   UserInfo,
 } from '../types/user-types.js';
 import { threeDays } from '../utils/date-utils.js';
 import type { EntityText } from '../utils/entity-text.js';
 import memoize2 from '../utils/memoize.js';
 import { useSelector } from '../utils/redux-utils.js';
 
 export type SidebarItem =
   | {
       ...SidebarInfo,
       +type: 'sidebar',
     }
   | {
       +type: 'seeMore',
       +unread: boolean,
     }
   | { +type: 'spacer' };
 
 export type ChatThreadItem = {
   +type: 'chatThreadItem',
   +threadInfo: ThreadInfo,
   +mostRecentNonLocalMessage: ?string,
   +lastUpdatedTime: number,
   +lastUpdatedTimeIncludingSidebars: number,
   +sidebars: $ReadOnlyArray<SidebarItem>,
   +pendingPersonalThreadUserInfo?: UserInfo,
 };
 
 const messageInfoSelector: (state: BaseAppState<>) => {
   +[id: string]: ?MessageInfo,
 } = createObjectSelector(
   (state: BaseAppState<>) => state.messageStore.messages,
   (state: BaseAppState<>) => state.currentUserInfo && state.currentUserInfo.id,
   (state: BaseAppState<>) => state.userStore.userInfos,
   threadInfoSelector,
   createMessageInfo,
 );
 
 function isEmptyMediaMessage(messageInfo: MessageInfo): boolean {
   return (
     (messageInfo.type === messageTypes.MULTIMEDIA ||
       messageInfo.type === messageTypes.IMAGES) &&
     messageInfo.media.length === 0
   );
 }
 
-function getLastUpdatedTime(
-  threadInfo: ThreadInfo,
-  messageStore: MessageStore,
-  messages: { +[id: string]: ?MessageInfo },
-): number {
-  const thread = messageStore.threads[threadInfo.id];
-  if (!thread) {
-    return threadInfo.creationTime;
-  }
-  for (const messageID of thread.messageIDs) {
-    const messageInfo = messages[messageID];
-    if (!messageInfo || isEmptyMediaMessage(messageInfo)) {
-      continue;
-    }
-    return messageInfo.time;
-  }
-  return threadInfo.creationTime;
-}
-
 function useCreateChatThreadItem(): ThreadInfo => ChatThreadItem {
   const messageInfos = useSelector(messageInfoSelector);
   const sidebarInfos = useSidebarInfos();
   const messageStore = useSelector(state => state.messageStore);
   return React.useCallback(
     threadInfo => {
       const mostRecentNonLocalMessage = getMostRecentNonLocalMessageID(
         threadInfo.id,
         messageStore,
       );
       const lastUpdatedTime = getLastUpdatedTime(
         threadInfo,
         messageStore,
         messageInfos,
       );
 
       const sidebars = sidebarInfos[threadInfo.id] ?? [];
       const allSidebarItems = sidebars.map(sidebarInfo => ({
         type: 'sidebar',
         ...sidebarInfo,
       }));
       const lastUpdatedTimeIncludingSidebars =
         allSidebarItems.length > 0
           ? Math.max(lastUpdatedTime, allSidebarItems[0].lastUpdatedTime)
           : lastUpdatedTime;
 
       const numUnreadSidebars = allSidebarItems.filter(
         sidebar => sidebar.threadInfo.currentUser.unread,
       ).length;
       let numReadSidebarsToShow = maxReadSidebars - numUnreadSidebars;
       const threeDaysAgo = Date.now() - threeDays;
 
       const sidebarItems: SidebarItem[] = [];
       for (const sidebar of allSidebarItems) {
         if (sidebarItems.length >= maxUnreadSidebars) {
           break;
         } else if (sidebar.threadInfo.currentUser.unread) {
           sidebarItems.push(sidebar);
         } else if (
           sidebar.lastUpdatedTime > threeDaysAgo &&
           numReadSidebarsToShow > 0
         ) {
           sidebarItems.push(sidebar);
           numReadSidebarsToShow--;
         }
       }
 
       const numReadButRecentSidebars = allSidebarItems.filter(
         sidebar =>
           !sidebar.threadInfo.currentUser.unread &&
           sidebar.lastUpdatedTime > threeDaysAgo,
       ).length;
       if (
         sidebarItems.length < numUnreadSidebars + numReadButRecentSidebars ||
         (sidebarItems.length < allSidebarItems.length &&
           sidebarItems.length > 0)
       ) {
         sidebarItems.push({
           type: 'seeMore',
           unread: numUnreadSidebars > maxUnreadSidebars,
         });
       }
       if (sidebarItems.length !== 0) {
         sidebarItems.push({
           type: 'spacer',
         });
       }
 
       return {
         type: 'chatThreadItem',
         threadInfo,
         mostRecentNonLocalMessage,
         lastUpdatedTime,
         lastUpdatedTimeIncludingSidebars,
         sidebars: sidebarItems,
       };
     },
     [messageInfos, messageStore, sidebarInfos],
   );
 }
 
 function useFlattenedChatListData(): $ReadOnlyArray<ChatThreadItem> {
   return useFilteredChatListData(threadInChatList);
 }
 
 function useFilteredChatListData(
   filterFunction: (threadInfo: ?(ThreadInfo | RawThreadInfo)) => boolean,
 ): $ReadOnlyArray<ChatThreadItem> {
   const threadInfos = useSelector(threadInfoSelector);
   const getChatThreadItem = useCreateChatThreadItem();
   return React.useMemo(
     () =>
       _flow(
         _filter(filterFunction),
         _map(getChatThreadItem),
         _orderBy('lastUpdatedTimeIncludingSidebars')('desc'),
       )(threadInfos),
     [getChatThreadItem, filterFunction, threadInfos],
   );
 }
 
 export type RobotextChatMessageInfoItem = {
   +itemType: 'message',
   +messageInfoType: 'robotext',
   +messageInfos: $ReadOnlyArray<RobotextMessageInfo>,
   +startsConversation: boolean,
   +startsCluster: boolean,
   endsCluster: boolean,
   +robotext: EntityText,
   +threadCreatedFromMessage: ?ThreadInfo,
   +reactions: ReactionInfo,
 };
 export type ComposableChatMessageInfoItem = {
   +itemType: 'message',
   +messageInfoType: 'composable',
   +messageInfo: ComposableMessageInfo,
   +localMessageInfo: ?LocalMessageInfo,
   +startsConversation: boolean,
   +startsCluster: boolean,
   endsCluster: boolean,
   +threadCreatedFromMessage: ?ThreadInfo,
   +reactions: ReactionInfo,
   +hasBeenEdited: boolean,
   +isPinned: boolean,
 };
 export type ChatMessageInfoItem =
   | RobotextChatMessageInfoItem
   | ComposableChatMessageInfoItem;
 export type ChatMessageItem = { itemType: 'loader' } | ChatMessageInfoItem;
 
 export type ReactionInfo = { +[reaction: string]: MessageReactionInfo };
 type MessageReactionInfo = {
   +viewerReacted: boolean,
   +users: $ReadOnlyArray<RelativeUserInfo>,
 };
 type TargetMessageReactions = Map<string, Map<string, RelativeUserInfo>>;
 
 const msInFiveMinutes = 5 * 60 * 1000;
 function createChatMessageItems(
   threadID: string,
   messageStore: MessageStore,
   messageInfos: { +[id: string]: ?MessageInfo },
   threadInfos: { +[id: string]: ThreadInfo },
   threadInfoFromSourceMessageID: {
     +[id: string]: ThreadInfo,
   },
   additionalMessages: $ReadOnlyArray<MessageInfo>,
   viewerID: string,
 ): ChatMessageItem[] {
   const thread = messageStore.threads[threadID];
 
   const threadMessageInfos = (thread?.messageIDs ?? [])
     .map((messageID: string) => messageInfos[messageID])
     .filter(Boolean);
   const messages =
     additionalMessages.length > 0
       ? sortMessageInfoList([...threadMessageInfos, ...additionalMessages])
       : threadMessageInfos;
 
   const targetMessageReactionsMap = new Map<string, TargetMessageReactions>();
 
   // We need to iterate backwards to put the order of messages in chronological
   // order, starting with the oldest. This avoids the scenario where the most
   // recent message with the remove_reaction action may try to remove a user
   // that hasn't been added to the messageReactionUsersInfoMap, causing it
   // to be skipped.
   for (let i = messages.length - 1; i >= 0; i--) {
     const messageInfo = messages[i];
     if (messageInfo.type !== messageTypes.REACTION) {
       continue;
     }
 
     if (!targetMessageReactionsMap.has(messageInfo.targetMessageID)) {
       const reactsMap: TargetMessageReactions = new Map();
       targetMessageReactionsMap.set(messageInfo.targetMessageID, reactsMap);
     }
 
     const messageReactsMap = targetMessageReactionsMap.get(
       messageInfo.targetMessageID,
     );
     invariant(messageReactsMap, 'messageReactsInfo should be set');
 
     if (!messageReactsMap.has(messageInfo.reaction)) {
       const usersInfoMap = new Map<string, RelativeUserInfo>();
       messageReactsMap.set(messageInfo.reaction, usersInfoMap);
     }
 
     const messageReactionUsersInfoMap = messageReactsMap.get(
       messageInfo.reaction,
     );
     invariant(
       messageReactionUsersInfoMap,
       'messageReactionUsersInfoMap should be set',
     );
 
     if (messageInfo.action === 'add_reaction') {
       messageReactionUsersInfoMap.set(
         messageInfo.creator.id,
         messageInfo.creator,
       );
     } else {
       messageReactionUsersInfoMap.delete(messageInfo.creator.id);
     }
   }
 
   const targetMessageEditMap = new Map<string, string>();
   for (let i = messages.length - 1; i >= 0; i--) {
     const messageInfo = messages[i];
     if (messageInfo.type !== messageTypes.EDIT_MESSAGE) {
       continue;
     }
     targetMessageEditMap.set(messageInfo.targetMessageID, messageInfo.text);
   }
 
   const targetMessagePinStatusMap = new Map<string, boolean>();
   // Once again, we iterate backwards to put the order of messages in
   // chronological order (i.e. oldest to newest) to handle pinned messages.
   // This is important because we want to make sure that the most recent pin
   // action is the one that is used to determine whether a message
   // is pinned or not.
   for (let i = messages.length - 1; i >= 0; i--) {
     const messageInfo = messages[i];
     if (messageInfo.type !== messageTypes.TOGGLE_PIN) {
       continue;
     }
 
     targetMessagePinStatusMap.set(
       messageInfo.targetMessageID,
       messageInfo.action === 'pin',
     );
   }
 
   const chatMessageItems: ChatMessageItem[] = [];
   let lastMessageInfo = null;
   for (let i = messages.length - 1; i >= 0; i--) {
     const messageInfo = messages[i];
 
     if (
       messageInfo.type === messageTypes.REACTION ||
       messageInfo.type === messageTypes.EDIT_MESSAGE
     ) {
       continue;
     }
 
     let originalMessageInfo =
       messageInfo.type === messageTypes.SIDEBAR_SOURCE
         ? messageInfo.sourceMessage
         : messageInfo;
 
     if (isEmptyMediaMessage(originalMessageInfo)) {
       continue;
     }
 
     let hasBeenEdited = false;
     if (
       originalMessageInfo.type === messageTypes.TEXT &&
       originalMessageInfo.id
     ) {
       const newText = targetMessageEditMap.get(originalMessageInfo.id);
       if (newText !== undefined) {
         hasBeenEdited = true;
         originalMessageInfo = {
           ...originalMessageInfo,
           text: newText,
         };
       }
     }
 
     let startsConversation = true;
     let startsCluster = true;
     if (
       lastMessageInfo &&
       lastMessageInfo.time + msInFiveMinutes > originalMessageInfo.time
     ) {
       startsConversation = false;
       if (
         isComposableMessageType(lastMessageInfo.type) &&
         isComposableMessageType(originalMessageInfo.type) &&
         lastMessageInfo.creator.id === originalMessageInfo.creator.id
       ) {
         startsCluster = false;
       }
     }
     if (startsCluster && chatMessageItems.length > 0) {
       const lastMessageItem = chatMessageItems[chatMessageItems.length - 1];
       invariant(lastMessageItem.itemType === 'message', 'should be message');
       lastMessageItem.endsCluster = true;
     }
     const threadCreatedFromMessage =
       !threadTypeIsSidebar(threadInfos[threadID]?.type) && messageInfo.id
         ? threadInfoFromSourceMessageID[messageInfo.id]
         : undefined;
 
     const isPinned = !!(
       originalMessageInfo.id &&
       targetMessagePinStatusMap.get(originalMessageInfo.id)
     );
 
     const renderedReactions: ReactionInfo = (() => {
       const result: { [string]: MessageReactionInfo } = {};
 
       let messageReactsMap;
       if (originalMessageInfo.id) {
         messageReactsMap = targetMessageReactionsMap.get(
           originalMessageInfo.id,
         );
       }
 
       if (!messageReactsMap) {
         return result;
       }
 
       for (const reaction of messageReactsMap.keys()) {
         const reactionUsersInfoMap = messageReactsMap.get(reaction);
         invariant(reactionUsersInfoMap, 'reactionUsersInfoMap should be set');
 
         if (reactionUsersInfoMap.size === 0) {
           continue;
         }
 
         const reactionUserInfos = [...reactionUsersInfoMap.values()];
 
         const messageReactionInfo = {
           users: reactionUserInfos,
           viewerReacted: reactionUsersInfoMap.has(viewerID),
         };
 
         result[reaction] = messageReactionInfo;
       }
 
       return result;
     })();
 
     const threadInfo = threadInfos[threadID];
     const parentThreadInfo = threadInfo?.parentThreadID
       ? threadInfos[threadInfo.parentThreadID]
       : null;
 
     const lastChatMessageItem =
       chatMessageItems.length > 0
         ? chatMessageItems[chatMessageItems.length - 1]
         : undefined;
     const messageSpec = messageSpecs[originalMessageInfo.type];
     if (
       !threadCreatedFromMessage &&
       Object.keys(renderedReactions).length === 0 &&
       !hasBeenEdited &&
       !isPinned &&
       lastChatMessageItem &&
       lastChatMessageItem.itemType === 'message' &&
       lastChatMessageItem.messageInfoType === 'robotext' &&
       !lastChatMessageItem.threadCreatedFromMessage &&
       Object.keys(lastChatMessageItem.reactions).length === 0 &&
       !isComposableMessageType(originalMessageInfo.type) &&
       messageSpec?.mergeIntoPrecedingRobotextMessageItem
     ) {
       const { mergeIntoPrecedingRobotextMessageItem } = messageSpec;
       const mergeResult = mergeIntoPrecedingRobotextMessageItem(
         originalMessageInfo,
         lastChatMessageItem,
         { threadInfo, parentThreadInfo },
       );
       if (mergeResult.shouldMerge) {
         chatMessageItems[chatMessageItems.length - 1] = mergeResult.item;
         continue;
       }
     }
 
     if (isComposableMessageType(originalMessageInfo.type)) {
       // We use these invariants instead of just checking the messageInfo.type
       // directly in the conditional above so that isComposableMessageType can
       // be the source of truth
       invariant(
         originalMessageInfo.type === messageTypes.TEXT ||
           originalMessageInfo.type === messageTypes.IMAGES ||
           originalMessageInfo.type === messageTypes.MULTIMEDIA,
         "Flow doesn't understand isComposableMessageType above",
       );
       const localMessageInfo =
         messageStore.local[messageKey(originalMessageInfo)];
       chatMessageItems.push({
         itemType: 'message',
         messageInfoType: 'composable',
         messageInfo: originalMessageInfo,
         localMessageInfo,
         startsConversation,
         startsCluster,
         endsCluster: false,
         threadCreatedFromMessage,
         reactions: renderedReactions,
         hasBeenEdited,
         isPinned,
       });
     } else {
       invariant(
         originalMessageInfo.type !== messageTypes.TEXT &&
           originalMessageInfo.type !== messageTypes.IMAGES &&
           originalMessageInfo.type !== messageTypes.MULTIMEDIA,
         "Flow doesn't understand isComposableMessageType above",
       );
       const robotext = robotextForMessageInfo(
         originalMessageInfo,
         threadInfo,
         parentThreadInfo,
       );
       chatMessageItems.push({
         itemType: 'message',
         messageInfoType: 'robotext',
         messageInfos: [originalMessageInfo],
         startsConversation,
         startsCluster,
         endsCluster: false,
         threadCreatedFromMessage,
         robotext,
         reactions: renderedReactions,
       });
     }
     lastMessageInfo = originalMessageInfo;
   }
   if (chatMessageItems.length > 0) {
     const lastMessageItem = chatMessageItems[chatMessageItems.length - 1];
     invariant(lastMessageItem.itemType === 'message', 'should be message');
     lastMessageItem.endsCluster = true;
   }
   chatMessageItems.reverse();
   const hideSpinner = thread ? thread.startReached : threadIsPending(threadID);
   if (hideSpinner) {
     return chatMessageItems;
   }
   return [...chatMessageItems, ({ itemType: 'loader' }: ChatMessageItem)];
 }
 
 const baseMessageListData = (
   threadID: ?string,
   additionalMessages: $ReadOnlyArray<MessageInfo>,
 ): ((state: BaseAppState<>) => ?(ChatMessageItem[])) =>
   createSelector(
     (state: BaseAppState<>) => state.messageStore,
     messageInfoSelector,
     threadInfoSelector,
     threadInfoFromSourceMessageIDSelector,
     (state: BaseAppState<>) =>
       state.currentUserInfo && state.currentUserInfo.id,
     (
       messageStore: MessageStore,
       messageInfos: { +[id: string]: ?MessageInfo },
       threadInfos: {
         +[id: string]: ThreadInfo,
       },
       threadInfoFromSourceMessageID: {
         +[id: string]: ThreadInfo,
       },
       viewerID: ?string,
     ): ?(ChatMessageItem[]) => {
       if (!threadID || !viewerID) {
         return null;
       }
       return createChatMessageItems(
         threadID,
         messageStore,
         messageInfos,
         threadInfos,
         threadInfoFromSourceMessageID,
         additionalMessages,
         viewerID,
       );
     },
   );
 export type MessageListData = ?(ChatMessageItem[]);
 const messageListData: (
   threadID: ?string,
   additionalMessages: $ReadOnlyArray<MessageInfo>,
 ) => (state: BaseAppState<>) => MessageListData = memoize2(baseMessageListData);
 
 export type UseMessageListDataArgs = {
   +searching: boolean,
   +userInfoInputArray: $ReadOnlyArray<AccountUserInfo>,
   +threadInfo: ?ThreadInfo,
 };
 
 function useMessageListData({
   searching,
   userInfoInputArray,
   threadInfo,
 }: UseMessageListDataArgs): MessageListData {
   const messageInfos = useSelector(messageInfoSelector);
 
   const containingThread = useSelector(state => {
     if (
       !threadInfo ||
       !threadTypeIsSidebar(threadInfo.type) ||
       !threadInfo.containingThreadID
     ) {
       return null;
     }
     return state.messageStore.threads[threadInfo.containingThreadID];
   });
 
   const pendingSidebarEditMessageInfo = React.useMemo(() => {
     const sourceMessageID = threadInfo?.sourceMessageID;
     const threadMessageInfos = (containingThread?.messageIDs ?? [])
       .map((messageID: string) => messageInfos[messageID])
       .filter(Boolean)
       .filter(
         message =>
           message.type === messageTypes.EDIT_MESSAGE &&
           message.targetMessageID === sourceMessageID,
       );
     if (threadMessageInfos.length === 0) {
       return null;
     }
     return threadMessageInfos[0];
   }, [threadInfo, containingThread, messageInfos]);
 
   const pendingSidebarSourceMessageInfo = useSelector(state => {
     const sourceMessageID = threadInfo?.sourceMessageID;
     if (
       !threadInfo ||
       !threadTypeIsSidebar(threadInfo.type) ||
       !sourceMessageID
     ) {
       return null;
     }
     const thread = state.messageStore.threads[threadInfo.id];
     const shouldSourceBeAdded =
       !thread ||
       (thread.startReached &&
         thread.messageIDs.every(
           id => messageInfos[id]?.type !== messageTypes.SIDEBAR_SOURCE,
         ));
     return shouldSourceBeAdded ? messageInfos[sourceMessageID] : null;
   });
 
   invariant(
     !pendingSidebarSourceMessageInfo ||
       pendingSidebarSourceMessageInfo.type !== messageTypes.SIDEBAR_SOURCE,
     'sidebars can not be created from sidebar_source message',
   );
 
   const additionalMessages = React.useMemo(() => {
     if (!pendingSidebarSourceMessageInfo) {
       return ([]: MessageInfo[]);
     }
     const result: MessageInfo[] = [pendingSidebarSourceMessageInfo];
     if (pendingSidebarEditMessageInfo) {
       result.push(pendingSidebarEditMessageInfo);
     }
     return result;
   }, [pendingSidebarSourceMessageInfo, pendingSidebarEditMessageInfo]);
   const boundMessageListData = useSelector(
     messageListData(threadInfo?.id, additionalMessages),
   );
 
   return React.useMemo(() => {
     if (searching && userInfoInputArray.length === 0) {
       return [];
     }
     return boundMessageListData;
   }, [searching, userInfoInputArray.length, boundMessageListData]);
 }
 
 export {
   messageInfoSelector,
   useCreateChatThreadItem,
   createChatMessageItems,
   messageListData,
   useFlattenedChatListData,
   useFilteredChatListData,
   useMessageListData,
 };