diff --git a/lib/shared/thread-utils.js b/lib/shared/thread-utils.js
index c767df2eb..1c1880693 100644
--- a/lib/shared/thread-utils.js
+++ b/lib/shared/thread-utils.js
@@ -1,802 +1,807 @@
 // @flow
 
 import invariant from 'invariant';
 import _find from 'lodash/fp/find';
 import * as React from 'react';
 import { type ParserRules } from 'simple-markdown';
 import tinycolor from 'tinycolor2';
 
 import {
   fetchMostRecentMessagesActionTypes,
   fetchMostRecentMessages,
 } from '../actions/message-actions';
 import {
   permissionLookup,
   getAllThreadPermissions,
   makePermissionsBlob,
 } from '../permissions/thread-permissions';
 import type { ChatThreadItem } from '../selectors/chat-selectors';
 import type {
   MultimediaMessageInfo,
   RobotextMessageInfo,
 } from '../types/message-types';
 import type { TextMessageInfo } from '../types/messages/text';
 import { userRelationshipStatus } from '../types/relationship-types';
 import {
   type RawThreadInfo,
   type ThreadInfo,
   type ThreadPermission,
   type MemberInfo,
   type ServerThreadInfo,
   type RelativeMemberInfo,
   type ThreadCurrentUserInfo,
   type RoleInfo,
   type ServerMemberInfo,
   type ThreadPermissionsInfo,
   type ThreadType,
   threadTypes,
   threadPermissions,
 } from '../types/thread-types';
 import { type UpdateInfo, updateTypes } from '../types/update-types';
 import type {
   GlobalAccountUserInfo,
   UserInfos,
   UserInfo,
 } from '../types/user-types';
 import { useDispatchActionPromise, useServerCall } from '../utils/action-utils';
 import { pluralize } from '../utils/text-utils';
 import { getMessageTitle } from './message-utils';
 import { relationshipBlockedInEitherDirection } from './relationship-utils';
 import threadWatcher from './thread-watcher';
 
 function colorIsDark(color: string) {
   return tinycolor(`#${color}`).isDark();
 }
 
 // Randomly distributed in RGB-space
 const hexNumerals = '0123456789abcdef';
 function generateRandomColor() {
   let color = '';
   for (let i = 0; i < 6; i++) {
     color += hexNumerals[Math.floor(Math.random() * 16)];
   }
   return color;
 }
 
 function generatePendingThreadColor(
   userIDs: $ReadOnlyArray<string>,
   viewerID: string,
 ) {
   const ids = [...userIDs, viewerID].sort().join('#');
 
   let hash = 0;
   for (let i = 0; i < ids.length; i++) {
     hash = 1009 * hash + ids.charCodeAt(i) * 83;
     hash %= 1000000007;
   }
   const hashString = hash.toString(16);
   return hashString.substring(hashString.length - 6).padStart(6, '8');
 }
 
 function threadHasPermission(
   threadInfo: ?(ThreadInfo | RawThreadInfo),
   permission: ThreadPermission,
 ): boolean {
   invariant(
     !permissionsDisabledByBlock.has(permission) || threadInfo?.uiName,
     `${permission} can be disabled by a block, but threadHasPermission can't ` +
       'check for a block on RawThreadInfo. Please pass in ThreadInfo instead!',
   );
   if (!threadInfo || !threadInfo.currentUser.permissions[permission]) {
     return false;
   }
   return threadInfo.currentUser.permissions[permission].value;
 }
 
 function viewerIsMember(threadInfo: ?(ThreadInfo | RawThreadInfo)): boolean {
   return !!(
     threadInfo &&
     threadInfo.currentUser.role !== null &&
     threadInfo.currentUser.role !== undefined
   );
 }
 
 function threadIsInHome(threadInfo: ?(ThreadInfo | RawThreadInfo)): boolean {
   return !!(threadInfo && threadInfo.currentUser.subscription.home);
 }
 
 // Can have messages
 function threadInChatList(threadInfo: ?(ThreadInfo | RawThreadInfo)): boolean {
   return (
     viewerIsMember(threadInfo) &&
     threadHasPermission(threadInfo, threadPermissions.VISIBLE)
   );
 }
 
 function threadIsTopLevel(threadInfo: ?(ThreadInfo | RawThreadInfo)): boolean {
   return !!(
     threadInChatList(threadInfo) &&
     threadInfo &&
     threadInfo.type !== threadTypes.SIDEBAR
   );
 }
 
 function threadInBackgroundChatList(
   threadInfo: ?(ThreadInfo | RawThreadInfo),
 ): boolean {
   return threadInChatList(threadInfo) && !threadIsInHome(threadInfo);
 }
 
 function threadInHomeChatList(
   threadInfo: ?(ThreadInfo | RawThreadInfo),
 ): boolean {
   return threadInChatList(threadInfo) && threadIsInHome(threadInfo);
 }
 
 // Can have Calendar entries,
 // does appear as a top-level entity in the thread list
 function threadInFilterList(
   threadInfo: ?(ThreadInfo | RawThreadInfo),
 ): boolean {
   return (
     threadInChatList(threadInfo) &&
     !!threadInfo &&
     threadInfo.type !== threadTypes.SIDEBAR
   );
 }
 
 function userIsMember(
   threadInfo: ?(ThreadInfo | RawThreadInfo),
   userID: string,
 ): boolean {
   if (!threadInfo) {
     return false;
   }
   return threadInfo.members.some(
     (member) =>
       member.id === userID && member.role !== null && member.role !== undefined,
   );
 }
 
 function threadActualMembers(
   memberInfos: $ReadOnlyArray<MemberInfo>,
 ): $ReadOnlyArray<string> {
   return memberInfos
     .filter(
       (memberInfo) => memberInfo.role !== null && memberInfo.role !== undefined,
     )
     .map((memberInfo) => memberInfo.id);
 }
 
 function threadIsGroupChat(threadInfo: ThreadInfo | RawThreadInfo) {
   return (
     threadInfo.members.filter(
       (member) =>
         member.role || member.permissions[threadPermissions.VOICED]?.value,
     ).length > 2
   );
 }
 
 function threadOrParentThreadIsGroupChat(
   threadInfo: RawThreadInfo | ThreadInfo,
 ) {
   return threadInfo.members.length > 2;
 }
 
 function threadIsPending(threadID: ?string) {
   return threadID?.startsWith('pending');
 }
 
 function threadIsPersonalAndPending(threadInfo: ?(ThreadInfo | RawThreadInfo)) {
   return (
     threadInfo?.type === threadTypes.PERSONAL && threadIsPending(threadInfo?.id)
   );
 }
 
 function getPendingThreadOtherUsers(threadInfo: ThreadInfo | RawThreadInfo) {
   invariant(threadIsPending(threadInfo.id), 'Thread should be pending');
 
   const otherUserIDs = threadInfo.id.split('/')[1];
   invariant(
-    otherUserIDs,
-    'Pending thread should contain other members id in its id',
+    otherUserIDs || threadInfo.type === threadTypes.SIDEBAR,
+    'Pending threads should contain other members id in its id',
   );
+
+  if (!otherUserIDs) {
+    return [];
+  }
   return otherUserIDs.split('+');
 }
 
 function getSingleOtherUser(
   threadInfo: ThreadInfo | RawThreadInfo,
   viewerID: ?string,
 ) {
   if (!viewerID) {
     return undefined;
   }
 
   const otherMemberIDs = threadInfo.members
     .map((member) => member.id)
     .filter((id) => id !== viewerID);
   if (otherMemberIDs.length !== 1) {
     return undefined;
   }
   return otherMemberIDs[0];
 }
 
 function getPendingThreadKey(memberIDs: $ReadOnlyArray<string>) {
   return [...memberIDs].sort().join('+');
 }
 
 type CreatePendingThreadArgs = {|
   +viewerID: string,
   +threadType: ThreadType,
   +members?: $ReadOnlyArray<GlobalAccountUserInfo | UserInfo>,
   +parentThreadID?: ?string,
   +threadColor?: ?string,
   +name?: ?string,
 |};
 
 function createPendingThread({
   viewerID,
   threadType,
   members,
   parentThreadID,
   threadColor,
   name,
 }: CreatePendingThreadArgs) {
   const now = Date.now();
   members = members ?? [];
   const memberIDs = members.map((member) => member.id);
   const threadID = `pending/${getPendingThreadKey(memberIDs)}`;
 
   const permissions = {
     [threadPermissions.KNOW_OF]: true,
     [threadPermissions.VISIBLE]: true,
     [threadPermissions.VOICED]: true,
   };
 
   const membershipPermissions = getAllThreadPermissions(
     makePermissionsBlob(permissions, null, threadID, threadType),
     threadID,
   );
   const role = {
     id: `${threadID}/role`,
     name: 'Members',
     permissions,
     isDefault: true,
   };
 
   const rawThreadInfo = {
     id: threadID,
     type: threadType,
     name: name ?? null,
     description: null,
     color: threadColor ?? generatePendingThreadColor(memberIDs, viewerID),
     creationTime: now,
     parentThreadID: parentThreadID ?? null,
     members: [
       {
         id: viewerID,
         role: role.id,
         permissions: membershipPermissions,
         isSender: false,
       },
       ...members.map((member) => ({
         id: member.id,
         role: role.id,
         permissions: membershipPermissions,
         isSender: false,
       })),
     ],
     roles: {
       [role.id]: role,
     },
     currentUser: {
       role: role.id,
       permissions: membershipPermissions,
       subscription: {
         pushNotifs: false,
         home: false,
       },
       unread: false,
     },
     repliesCount: 0,
   };
 
   const userInfos = {};
   members.forEach((member) => (userInfos[member.id] = member));
 
   return threadInfoFromRawThreadInfo(rawThreadInfo, viewerID, userInfos);
 }
 
 function createPendingThreadItem(
   viewerID: string,
   user: GlobalAccountUserInfo,
 ): ChatThreadItem {
   const threadInfo = createPendingThread({
     viewerID,
     threadType: threadTypes.PERSONAL,
     members: [user],
   });
 
   return {
     type: 'chatThreadItem',
     threadInfo,
     mostRecentMessageInfo: null,
     mostRecentNonLocalMessage: null,
     lastUpdatedTime: threadInfo.creationTime,
     lastUpdatedTimeIncludingSidebars: threadInfo.creationTime,
     sidebars: [],
     pendingPersonalThreadUserInfo: {
       id: user.id,
       username: user.username,
     },
   };
 }
 
 function createPendingSidebar(
   messageInfo: TextMessageInfo | MultimediaMessageInfo | RobotextMessageInfo,
   threadInfo: ThreadInfo,
   viewerID: string,
   markdownRules: ParserRules,
 ) {
   const { id, username } = messageInfo.creator;
   const { id: parentThreadID, color } = threadInfo;
 
   invariant(username, 'username should be set in createPendingSidebar');
   const initialMemberUserInfo: GlobalAccountUserInfo = { id, username };
+  const creatorIsMember = userIsMember(threadInfo, id);
   return createPendingThread({
     viewerID,
     threadType: threadTypes.SIDEBAR,
-    members: [initialMemberUserInfo],
+    members: creatorIsMember ? [initialMemberUserInfo] : [],
     parentThreadID,
     threadColor: color,
     name: getMessageTitle(messageInfo, threadInfo, markdownRules),
   });
 }
 
 function pendingThreadType(numberOfOtherMembers: number) {
   return numberOfOtherMembers === 1
     ? threadTypes.PERSONAL
     : threadTypes.CHAT_SECRET;
 }
 
 type RawThreadInfoOptions = {|
   +includeVisibilityRules?: ?boolean,
   +filterMemberList?: ?boolean,
 |};
 function rawThreadInfoFromServerThreadInfo(
   serverThreadInfo: ServerThreadInfo,
   viewerID: string,
   options?: RawThreadInfoOptions,
 ): ?RawThreadInfo {
   const includeVisibilityRules = options?.includeVisibilityRules;
   const filterMemberList = options?.filterMemberList;
 
   const members = [];
   let currentUser;
   for (const serverMember of serverThreadInfo.members) {
     if (
       filterMemberList &&
       serverMember.id !== viewerID &&
       !serverMember.role &&
       !memberHasAdminPowers(serverMember)
     ) {
       continue;
     }
     members.push({
       id: serverMember.id,
       role: serverMember.role,
       permissions: serverMember.permissions,
       isSender: serverMember.isSender,
     });
     if (serverMember.id === viewerID) {
       currentUser = {
         role: serverMember.role,
         permissions: serverMember.permissions,
         subscription: serverMember.subscription,
         unread: serverMember.unread,
       };
     }
   }
 
   let currentUserPermissions;
   if (currentUser) {
     currentUserPermissions = currentUser.permissions;
   } else {
     currentUserPermissions = getAllThreadPermissions(null, serverThreadInfo.id);
     currentUser = {
       role: null,
       permissions: currentUserPermissions,
       subscription: {
         home: false,
         pushNotifs: false,
       },
       unread: null,
     };
   }
   if (!permissionLookup(currentUserPermissions, threadPermissions.KNOW_OF)) {
     return null;
   }
 
   const rawThreadInfo: RawThreadInfo = {
     id: serverThreadInfo.id,
     type: serverThreadInfo.type,
     name: serverThreadInfo.name,
     description: serverThreadInfo.description,
     color: serverThreadInfo.color,
     creationTime: serverThreadInfo.creationTime,
     parentThreadID: serverThreadInfo.parentThreadID,
     members,
     roles: serverThreadInfo.roles,
     currentUser,
     repliesCount: serverThreadInfo.repliesCount,
   };
   const sourceMessageID = serverThreadInfo.sourceMessageID;
   if (sourceMessageID) {
     rawThreadInfo.sourceMessageID = sourceMessageID;
   }
   if (!includeVisibilityRules) {
     return rawThreadInfo;
   }
   return ({
     ...rawThreadInfo,
     visibilityRules: rawThreadInfo.type,
   }: any);
 }
 
 function robotextName(
   threadInfo: RawThreadInfo | ThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
 ): string {
   const threadUsernames: string[] = threadInfo.members
     .filter(
       (threadMember) =>
         threadMember.id !== viewerID &&
         (threadMember.role || memberHasAdminPowers(threadMember)),
     )
     .map(
       (threadMember) =>
         userInfos[threadMember.id] && userInfos[threadMember.id].username,
     )
     .filter(Boolean);
   if (threadUsernames.length === 0) {
     return 'just you';
   }
   return pluralize(threadUsernames);
 }
 
 function threadUIName(
   threadInfo: RawThreadInfo | ThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
 ): string {
   if (threadInfo.name) {
     return threadInfo.name;
   }
   return robotextName(threadInfo, viewerID, userInfos);
 }
 
 function threadInfoFromRawThreadInfo(
   rawThreadInfo: RawThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
 ): ThreadInfo {
   const threadInfo: ThreadInfo = {
     id: rawThreadInfo.id,
     type: rawThreadInfo.type,
     name: rawThreadInfo.name,
     uiName: threadUIName(rawThreadInfo, viewerID, userInfos),
     description: rawThreadInfo.description,
     color: rawThreadInfo.color,
     creationTime: rawThreadInfo.creationTime,
     parentThreadID: rawThreadInfo.parentThreadID,
     members: rawThreadInfo.members,
     roles: rawThreadInfo.roles,
     currentUser: getCurrentUser(rawThreadInfo, viewerID, userInfos),
     repliesCount: rawThreadInfo.repliesCount,
   };
   const { sourceMessageID } = rawThreadInfo;
   if (sourceMessageID) {
     threadInfo.sourceMessageID = sourceMessageID;
   }
   return threadInfo;
 }
 
 function getCurrentUser(
   threadInfo: RawThreadInfo | ThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
 ): ThreadCurrentUserInfo {
   if (!threadFrozenDueToBlock(threadInfo, viewerID, userInfos)) {
     return threadInfo.currentUser;
   }
 
   return {
     ...threadInfo.currentUser,
     permissions: {
       ...threadInfo.currentUser.permissions,
       ...disabledPermissions,
     },
   };
 }
 
 function threadIsWithBlockedUserOnly(
   threadInfo: RawThreadInfo | ThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
   checkOnlyViewerBlock?: boolean,
 ): boolean {
   if (
     threadOrParentThreadIsGroupChat(threadInfo) ||
     threadOrParentThreadHasAdminRole(threadInfo)
   ) {
     return false;
   }
 
   const otherUserID = getSingleOtherUser(threadInfo, viewerID);
   if (!otherUserID) {
     return false;
   }
   const otherUserRelationshipStatus =
     userInfos[otherUserID]?.relationshipStatus;
 
   if (checkOnlyViewerBlock) {
     return (
       otherUserRelationshipStatus === userRelationshipStatus.BLOCKED_BY_VIEWER
     );
   }
 
   return (
     !!otherUserRelationshipStatus &&
     relationshipBlockedInEitherDirection(otherUserRelationshipStatus)
   );
 }
 
 function threadFrozenDueToBlock(
   threadInfo: RawThreadInfo | ThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
 ): boolean {
   return threadIsWithBlockedUserOnly(threadInfo, viewerID, userInfos);
 }
 
 function threadFrozenDueToViewerBlock(
   threadInfo: RawThreadInfo | ThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
 ): boolean {
   return threadIsWithBlockedUserOnly(threadInfo, viewerID, userInfos, true);
 }
 
 function rawThreadInfoFromThreadInfo(threadInfo: ThreadInfo): RawThreadInfo {
   const rawThreadInfo: RawThreadInfo = {
     id: threadInfo.id,
     type: threadInfo.type,
     name: threadInfo.name,
     description: threadInfo.description,
     color: threadInfo.color,
     creationTime: threadInfo.creationTime,
     parentThreadID: threadInfo.parentThreadID,
     members: threadInfo.members,
     roles: threadInfo.roles,
     currentUser: threadInfo.currentUser,
     repliesCount: threadInfo.repliesCount,
   };
   const { sourceMessageID } = threadInfo;
   if (sourceMessageID) {
     rawThreadInfo.sourceMessageID = sourceMessageID;
   }
   return rawThreadInfo;
 }
 
 const threadTypeDescriptions = {
   [threadTypes.CHAT_NESTED_OPEN]:
     'Anybody in the parent thread can see an open child thread.',
   [threadTypes.CHAT_SECRET]:
     'Only visible to its members and admins of ancestor threads.',
 };
 
 function usersInThreadInfo(threadInfo: RawThreadInfo | ThreadInfo): string[] {
   const userIDs = new Set();
   for (let member of threadInfo.members) {
     userIDs.add(member.id);
   }
   return [...userIDs];
 }
 
 function memberIsAdmin(
   memberInfo: RelativeMemberInfo | MemberInfo,
   threadInfo: ThreadInfo | RawThreadInfo,
 ) {
   return memberInfo.role && roleIsAdminRole(threadInfo.roles[memberInfo.role]);
 }
 
 // Since we don't have access to all of the ancestor ThreadInfos, we approximate
 // "parent admin" as anybody with CHANGE_ROLE permissions.
 function memberHasAdminPowers(
   memberInfo: RelativeMemberInfo | MemberInfo | ServerMemberInfo,
 ): boolean {
   return !!memberInfo.permissions[threadPermissions.CHANGE_ROLE]?.value;
 }
 
 function roleIsAdminRole(roleInfo: ?RoleInfo) {
   return roleInfo && !roleInfo.isDefault && roleInfo.name === 'Admins';
 }
 
 function threadHasAdminRole(
   threadInfo: ?(RawThreadInfo | ThreadInfo | ServerThreadInfo),
 ) {
   if (!threadInfo) {
     return false;
   }
   return _find({ name: 'Admins' })(threadInfo.roles);
 }
 
 function threadOrParentThreadHasAdminRole(
   threadInfo: RawThreadInfo | ThreadInfo,
 ) {
   return (
     threadInfo.members.filter((member) => memberHasAdminPowers(member)).length >
     0
   );
 }
 
 function identifyInvalidatedThreads(
   updateInfos: $ReadOnlyArray<UpdateInfo>,
 ): Set<string> {
   const invalidated = new Set();
   for (const updateInfo of updateInfos) {
     if (updateInfo.type === updateTypes.DELETE_THREAD) {
       invalidated.add(updateInfo.threadID);
     }
   }
   return invalidated;
 }
 
 const permissionsDisabledByBlockArray = [
   threadPermissions.VOICED,
   threadPermissions.EDIT_ENTRIES,
   threadPermissions.EDIT_THREAD,
   threadPermissions.CREATE_SUBTHREADS,
   threadPermissions.CREATE_SIDEBARS,
   threadPermissions.JOIN_THREAD,
   threadPermissions.EDIT_PERMISSIONS,
   threadPermissions.ADD_MEMBERS,
   threadPermissions.REMOVE_MEMBERS,
 ];
 
 const permissionsDisabledByBlock: Set<ThreadPermission> = new Set(
   permissionsDisabledByBlockArray,
 );
 
 const disabledPermissions: ThreadPermissionsInfo = permissionsDisabledByBlockArray.reduce(
   (permissions: ThreadPermissionsInfo, permission: string) => ({
     ...permissions,
     [permission]: { value: false, source: null },
   }),
   {},
 );
 
 // Consider updating itemHeight in native/chat/chat-thread-list.react.js
 // if you change this
 const emptyItemText =
   `Background threads are just like normal threads, except they don't ` +
   `contribute to your unread count.\n\n` +
   `To move a thread over here, switch the “Background” option in its settings.`;
 
 const threadSearchText = (
   threadInfo: RawThreadInfo | ThreadInfo,
   userInfos: UserInfos,
 ): string => {
   const searchTextArray = [];
   if (threadInfo.name) {
     searchTextArray.push(threadInfo.name);
   }
   if (threadInfo.description) {
     searchTextArray.push(threadInfo.description);
   }
   for (let member of threadInfo.members) {
     const isParentAdmin = memberHasAdminPowers(member);
     if (!member.role && !isParentAdmin) {
       continue;
     }
 
     const userInfo = userInfos[member.id];
     if (userInfo && userInfo.username) {
       searchTextArray.push(userInfo.username);
     }
   }
   return searchTextArray.join(' ');
 };
 
 function threadNoun(threadType: ThreadType) {
   return threadType === threadTypes.SIDEBAR ? 'sidebar' : 'thread';
 }
 
 function threadLabel(threadType: ThreadType) {
   if (threadType === threadTypes.CHAT_SECRET) {
     return 'Secret';
   } else if (threadType === threadTypes.PERSONAL) {
     return 'Personal';
   } else if (threadType === threadTypes.SIDEBAR) {
     return 'Sidebar';
   } else if (threadType === threadTypes.PRIVATE) {
     return 'Private';
   } else if (threadType === threadTypes.CHAT_NESTED_OPEN) {
     return 'Open';
   }
   invariant(false, `unexpected threadType ${threadType}`);
 }
 
 function useWatchThread(threadInfo: ?ThreadInfo) {
   const dispatchActionPromise = useDispatchActionPromise();
   const callFetchMostRecentMessages = useServerCall(fetchMostRecentMessages);
 
   const threadID = threadInfo?.id;
   const threadNotInChatList = !threadInChatList(threadInfo);
   React.useEffect(() => {
     if (threadID && threadNotInChatList) {
       threadWatcher.watchID(threadID);
       dispatchActionPromise(
         fetchMostRecentMessagesActionTypes,
         callFetchMostRecentMessages(threadID),
       );
     }
     return () => {
       if (threadID && threadNotInChatList) {
         threadWatcher.removeID(threadID);
       }
     };
   }, [
     callFetchMostRecentMessages,
     dispatchActionPromise,
     threadNotInChatList,
     threadID,
   ]);
 }
 
 export {
   colorIsDark,
   generateRandomColor,
   generatePendingThreadColor,
   threadHasPermission,
   viewerIsMember,
   threadInChatList,
   threadIsTopLevel,
   threadInBackgroundChatList,
   threadInHomeChatList,
   threadIsInHome,
   threadInFilterList,
   userIsMember,
   threadActualMembers,
   threadIsGroupChat,
   threadIsPending,
   threadIsPersonalAndPending,
   getPendingThreadOtherUsers,
   getSingleOtherUser,
   getPendingThreadKey,
   createPendingThread,
   createPendingThreadItem,
   createPendingSidebar,
   pendingThreadType,
   getCurrentUser,
   threadFrozenDueToBlock,
   threadFrozenDueToViewerBlock,
   rawThreadInfoFromServerThreadInfo,
   robotextName,
   threadInfoFromRawThreadInfo,
   rawThreadInfoFromThreadInfo,
   threadTypeDescriptions,
   usersInThreadInfo,
   memberIsAdmin,
   memberHasAdminPowers,
   roleIsAdminRole,
   threadHasAdminRole,
   identifyInvalidatedThreads,
   permissionsDisabledByBlock,
   emptyItemText,
   threadSearchText,
   threadNoun,
   threadLabel,
   useWatchThread,
 };
diff --git a/native/chat/chat-input-bar.react.js b/native/chat/chat-input-bar.react.js
index a2fea51cf..10030b97d 100644
--- a/native/chat/chat-input-bar.react.js
+++ b/native/chat/chat-input-bar.react.js
@@ -1,952 +1,956 @@
 // @flow
 
 import invariant from 'invariant';
 import _throttle from 'lodash/throttle';
 import PropTypes from 'prop-types';
 import * as React from 'react';
 import {
   View,
   TextInput,
   TouchableOpacity,
   Platform,
   Text,
   ActivityIndicator,
   TouchableWithoutFeedback,
   Alert,
   NativeAppEventEmitter,
 } from 'react-native';
 import { TextInputKeyboardMangerIOS } from 'react-native-keyboard-input';
 import Animated, { Easing } from 'react-native-reanimated';
 import FAIcon from 'react-native-vector-icons/FontAwesome';
 import Icon from 'react-native-vector-icons/Ionicons';
 import { useDispatch } from 'react-redux';
 
 import { saveDraftActionType } from 'lib/actions/miscellaneous-action-types';
 import {
   joinThreadActionTypes,
   joinThread,
   newThread,
   newThreadActionTypes,
 } from 'lib/actions/thread-actions';
 import { createLoadingStatusSelector } from 'lib/selectors/loading-selectors';
 import { trimMessage } from 'lib/shared/message-utils';
 import {
   threadHasPermission,
   viewerIsMember,
   threadFrozenDueToViewerBlock,
   threadActualMembers,
   threadIsPending,
   getPendingThreadOtherUsers,
   pendingThreadType,
 } from 'lib/shared/thread-utils';
 import type { CalendarQuery } from 'lib/types/entry-types';
 import { loadingStatusPropType } from 'lib/types/loading-types';
 import type { LoadingStatus } from 'lib/types/loading-types';
 import type { PhotoPaste } from 'lib/types/media-types';
 import { messageTypes } from 'lib/types/message-types';
 import type { Dispatch } from 'lib/types/redux-types';
 import {
   type ThreadInfo,
   threadInfoPropType,
   threadPermissions,
   type ClientThreadJoinRequest,
   type ThreadJoinPayload,
   type NewThreadRequest,
   type NewThreadResult,
   threadTypes,
 } from 'lib/types/thread-types';
 import { type UserInfos, userInfoPropType } from 'lib/types/user-types';
 import {
   type DispatchActionPromise,
   useServerCall,
   useDispatchActionPromise,
 } from 'lib/utils/action-utils';
 
 import Button from '../components/button.react';
 import ClearableTextInput from '../components/clearable-text-input.react';
 import {
   type InputState,
   inputStatePropType,
   InputStateContext,
 } from '../input/input-state';
 import { getKeyboardHeight } from '../keyboard/keyboard';
 import KeyboardInputHost from '../keyboard/keyboard-input-host.react';
 import {
   type KeyboardState,
   keyboardStatePropType,
   KeyboardContext,
 } from '../keyboard/keyboard-state';
 import {
   nonThreadCalendarQuery,
   activeThreadSelector,
 } from '../navigation/nav-selectors';
 import { NavContext } from '../navigation/navigation-context';
 import {
   type NavigationRoute,
   CameraModalRouteName,
   ImagePasteModalRouteName,
 } from '../navigation/route-names';
 import { useSelector } from '../redux/redux-utils';
 import {
   type Colors,
   colorsPropType,
   useStyles,
   useColors,
 } from '../themes/colors';
 import type { ViewStyle } from '../types/styles';
 import { runTiming } from '../utils/animation-utils';
 import type { ChatNavigationProp } from './chat.react';
 import {
   messageListRoutePropType,
   messageListNavPropType,
 } from './message-list-types';
 
 /* eslint-disable import/no-named-as-default-member */
 const {
   Value,
   Clock,
   block,
   set,
   cond,
   neq,
   sub,
   interpolate,
   stopClock,
 } = Animated;
 /* eslint-enable import/no-named-as-default-member */
 
 const expandoButtonsAnimationConfig = {
   duration: 500,
   easing: Easing.inOut(Easing.ease),
 };
 const sendButtonAnimationConfig = {
   duration: 150,
   easing: Easing.inOut(Easing.ease),
 };
 
 const draftKeyFromThreadID = (threadID: string) =>
   `${threadID}/message_composer`;
 
 type BaseProps = {|
   +threadInfo: ThreadInfo,
   +navigation: ChatNavigationProp<'MessageList'>,
   +route: NavigationRoute<'MessageList'>,
 |};
 type Props = {|
   ...BaseProps,
   // Redux state
   +viewerID: ?string,
   +draft: string,
   +joinThreadLoadingStatus: LoadingStatus,
   +calendarQuery: () => CalendarQuery,
   +nextLocalID: number,
   +userInfos: UserInfos,
   +colors: Colors,
   +styles: typeof unboundStyles,
   // connectNav
   +isActive: boolean,
   // withKeyboardState
   +keyboardState: ?KeyboardState,
   // Redux dispatch functions
   +dispatch: Dispatch,
   +dispatchActionPromise: DispatchActionPromise,
   // async functions that hit server APIs
   +joinThread: (request: ClientThreadJoinRequest) => Promise<ThreadJoinPayload>,
   +newThread: (request: NewThreadRequest) => Promise<NewThreadResult>,
   // withInputState
   +inputState: ?InputState,
 |};
 type State = {|
   +text: string,
   +buttonsExpanded: boolean,
 |};
 class ChatInputBar extends React.PureComponent<Props, State> {
   static propTypes = {
     threadInfo: threadInfoPropType.isRequired,
     navigation: messageListNavPropType.isRequired,
     route: messageListRoutePropType.isRequired,
     isActive: PropTypes.bool.isRequired,
     viewerID: PropTypes.string,
     draft: PropTypes.string.isRequired,
     joinThreadLoadingStatus: loadingStatusPropType.isRequired,
     calendarQuery: PropTypes.func.isRequired,
     nextLocalID: PropTypes.number.isRequired,
     userInfos: PropTypes.objectOf(userInfoPropType).isRequired,
     colors: colorsPropType.isRequired,
     styles: PropTypes.objectOf(PropTypes.object).isRequired,
     keyboardState: keyboardStatePropType,
     dispatch: PropTypes.func.isRequired,
     dispatchActionPromise: PropTypes.func.isRequired,
     joinThread: PropTypes.func.isRequired,
     inputState: inputStatePropType,
     newThread: PropTypes.func.isRequired,
   };
   textInput: ?React.ElementRef<typeof TextInput>;
   clearableTextInput: ?ClearableTextInput;
 
   expandoButtonsOpen: Value;
   targetExpandoButtonsOpen: Value;
   expandoButtonsStyle: ViewStyle;
   cameraRollIconStyle: ViewStyle;
   cameraIconStyle: ViewStyle;
   expandIconStyle: ViewStyle;
 
   sendButtonContainerOpen: Value;
   targetSendButtonContainerOpen: Value;
   sendButtonContainerStyle: ViewStyle;
 
   newThreadID: ?string;
 
   constructor(props: Props) {
     super(props);
     this.state = {
       text: props.draft,
       buttonsExpanded: true,
     };
 
     this.expandoButtonsOpen = new Value(1);
     this.targetExpandoButtonsOpen = new Value(1);
     const prevTargetExpandoButtonsOpen = new Value(1);
     const expandoButtonClock = new Clock();
     const expandoButtonsOpen = block([
       cond(neq(this.targetExpandoButtonsOpen, prevTargetExpandoButtonsOpen), [
         stopClock(expandoButtonClock),
         set(prevTargetExpandoButtonsOpen, this.targetExpandoButtonsOpen),
       ]),
       cond(
         neq(this.expandoButtonsOpen, this.targetExpandoButtonsOpen),
         set(
           this.expandoButtonsOpen,
           runTiming(
             expandoButtonClock,
             this.expandoButtonsOpen,
             this.targetExpandoButtonsOpen,
             true,
             expandoButtonsAnimationConfig,
           ),
         ),
       ),
       this.expandoButtonsOpen,
     ]);
 
     this.cameraRollIconStyle = {
       ...unboundStyles.cameraRollIcon,
       opacity: expandoButtonsOpen,
     };
     this.cameraIconStyle = {
       ...unboundStyles.cameraIcon,
       opacity: expandoButtonsOpen,
     };
 
     const expandoButtonsWidth = interpolate(expandoButtonsOpen, {
       inputRange: [0, 1],
       outputRange: [22, 60],
     });
     this.expandoButtonsStyle = {
       ...unboundStyles.expandoButtons,
       width: expandoButtonsWidth,
     };
 
     const expandOpacity = sub(1, expandoButtonsOpen);
     this.expandIconStyle = {
       ...unboundStyles.expandIcon,
       opacity: expandOpacity,
     };
 
     const initialSendButtonContainerOpen = trimMessage(props.draft) ? 1 : 0;
     this.sendButtonContainerOpen = new Value(initialSendButtonContainerOpen);
     this.targetSendButtonContainerOpen = new Value(
       initialSendButtonContainerOpen,
     );
     const prevTargetSendButtonContainerOpen = new Value(
       initialSendButtonContainerOpen,
     );
     const sendButtonClock = new Clock();
     const sendButtonContainerOpen = block([
       cond(
         neq(
           this.targetSendButtonContainerOpen,
           prevTargetSendButtonContainerOpen,
         ),
         [
           stopClock(sendButtonClock),
           set(
             prevTargetSendButtonContainerOpen,
             this.targetSendButtonContainerOpen,
           ),
         ],
       ),
       cond(
         neq(this.sendButtonContainerOpen, this.targetSendButtonContainerOpen),
         set(
           this.sendButtonContainerOpen,
           runTiming(
             sendButtonClock,
             this.sendButtonContainerOpen,
             this.targetSendButtonContainerOpen,
             true,
             sendButtonAnimationConfig,
           ),
         ),
       ),
       this.sendButtonContainerOpen,
     ]);
 
     const sendButtonContainerWidth = interpolate(sendButtonContainerOpen, {
       inputRange: [0, 1],
       outputRange: [4, 38],
     });
     this.sendButtonContainerStyle = { width: sendButtonContainerWidth };
   }
 
   static mediaGalleryOpen(props: Props) {
     const { keyboardState } = props;
     return !!(keyboardState && keyboardState.mediaGalleryOpen);
   }
 
   static systemKeyboardShowing(props: Props) {
     const { keyboardState } = props;
     return !!(keyboardState && keyboardState.systemKeyboardShowing);
   }
 
   get systemKeyboardShowing() {
     return ChatInputBar.systemKeyboardShowing(this.props);
   }
 
   immediatelyShowSendButton() {
     this.sendButtonContainerOpen.setValue(1);
     this.targetSendButtonContainerOpen.setValue(1);
   }
 
   updateSendButton(currentText: string) {
     this.targetSendButtonContainerOpen.setValue(currentText === '' ? 0 : 1);
   }
 
   componentDidMount() {
     if (this.props.isActive) {
       this.addReplyListener();
     }
   }
 
   componentWillUnmount() {
     if (this.props.isActive) {
       this.removeReplyListener();
     }
   }
 
   componentDidUpdate(prevProps: Props, prevState: State) {
     if (this.props.isActive && !prevProps.isActive) {
       this.addReplyListener();
     } else if (!this.props.isActive && prevProps.isActive) {
       this.removeReplyListener();
     }
 
     const currentText = trimMessage(this.state.text);
     const prevText = trimMessage(prevState.text);
 
     if (
       (currentText === '' && prevText !== '') ||
       (currentText !== '' && prevText === '')
     ) {
       this.updateSendButton(currentText);
     }
 
     const systemKeyboardIsShowing = ChatInputBar.systemKeyboardShowing(
       this.props,
     );
     const systemKeyboardWasShowing = ChatInputBar.systemKeyboardShowing(
       prevProps,
     );
     if (systemKeyboardIsShowing && !systemKeyboardWasShowing) {
       this.hideButtons();
     } else if (!systemKeyboardIsShowing && systemKeyboardWasShowing) {
       this.expandButtons();
     }
 
     const imageGalleryIsOpen = ChatInputBar.mediaGalleryOpen(this.props);
     const imageGalleryWasOpen = ChatInputBar.mediaGalleryOpen(prevProps);
     if (!imageGalleryIsOpen && imageGalleryWasOpen) {
       this.hideButtons();
     } else if (imageGalleryIsOpen && !imageGalleryWasOpen) {
       this.expandButtons();
       this.setIOSKeyboardHeight();
     }
   }
 
   addReplyListener() {
     invariant(
       this.props.inputState,
       'inputState should be set in addReplyListener',
     );
     this.props.inputState.addReplyListener(this.focusAndUpdateText);
   }
 
   removeReplyListener() {
     invariant(
       this.props.inputState,
       'inputState should be set in removeReplyListener',
     );
     this.props.inputState.removeReplyListener(this.focusAndUpdateText);
   }
 
   setIOSKeyboardHeight() {
     if (Platform.OS !== 'ios') {
       return;
     }
     const { textInput } = this;
     if (!textInput) {
       return;
     }
     const keyboardHeight = getKeyboardHeight();
     if (keyboardHeight === null || keyboardHeight === undefined) {
       return;
     }
     TextInputKeyboardMangerIOS.setKeyboardHeight(textInput, keyboardHeight);
   }
 
   render() {
     const isMember = viewerIsMember(this.props.threadInfo);
     const canJoin = threadHasPermission(
       this.props.threadInfo,
       threadPermissions.JOIN_THREAD,
     );
     let joinButton = null;
     if (!isMember && canJoin) {
       let buttonContent;
       if (this.props.joinThreadLoadingStatus === 'loading') {
         buttonContent = (
           <ActivityIndicator
             size="small"
             color="white"
             style={this.props.styles.joinThreadLoadingIndicator}
           />
         );
       } else {
         buttonContent = (
           <Text style={this.props.styles.joinButtonText}>Join Thread</Text>
         );
       }
       joinButton = (
         <View style={this.props.styles.joinButtonContainer}>
           <Button
             onPress={this.onPressJoin}
             iosActiveOpacity={0.5}
             style={this.props.styles.joinButton}
           >
             {buttonContent}
           </Button>
         </View>
       );
     }
 
     let content;
     if (threadHasPermission(this.props.threadInfo, threadPermissions.VOICED)) {
       content = this.renderInput();
     } else if (
       threadFrozenDueToViewerBlock(
         this.props.threadInfo,
         this.props.viewerID,
         this.props.userInfos,
       ) &&
       threadActualMembers(this.props.threadInfo.members).length === 2
     ) {
       content = (
         <Text style={this.props.styles.explanation}>
           You can&apos;t send messages to a user that you&apos;ve blocked.
         </Text>
       );
     } else if (isMember) {
       content = (
         <Text style={this.props.styles.explanation}>
           You don&apos;t have permission to send messages.
         </Text>
       );
     } else {
       const defaultRoleID = Object.keys(this.props.threadInfo.roles).find(
         (roleID) => this.props.threadInfo.roles[roleID].isDefault,
       );
       invariant(
         defaultRoleID !== undefined,
         'all threads should have a default role',
       );
       const defaultRole = this.props.threadInfo.roles[defaultRoleID];
       const membersAreVoiced = !!defaultRole.permissions[
         threadPermissions.VOICED
       ];
       if (membersAreVoiced && canJoin) {
         content = (
           <Text style={this.props.styles.explanation}>
             Join this thread to send messages.
           </Text>
         );
       } else {
         content = (
           <Text style={this.props.styles.explanation}>
             You don&apos;t have permission to send messages.
           </Text>
         );
       }
     }
 
     const keyboardInputHost =
       Platform.OS === 'android' ? null : (
         <KeyboardInputHost textInputRef={this.textInput} />
       );
 
     return (
       <View style={this.props.styles.container}>
         {joinButton}
         {content}
         {keyboardInputHost}
       </View>
     );
   }
 
   renderInput() {
     const expandoButton = (
       <TouchableOpacity
         onPress={this.expandButtons}
         activeOpacity={0.4}
         style={this.props.styles.expandButton}
       >
         <Animated.View style={this.expandIconStyle}>
           <FAIcon
             name="chevron-right"
             size={19}
             color={this.props.colors.listInputButton}
           />
         </Animated.View>
       </TouchableOpacity>
     );
     const threadColor = `#${this.props.threadInfo.color}`;
     return (
       <TouchableWithoutFeedback onPress={this.dismissKeyboard}>
         <View style={this.props.styles.inputContainer}>
           <Animated.View style={this.expandoButtonsStyle}>
             <View style={this.props.styles.innerExpandoButtons}>
               {this.state.buttonsExpanded ? expandoButton : null}
               <TouchableOpacity
                 onPress={this.showMediaGallery}
                 activeOpacity={0.4}
               >
                 <Animated.View style={this.cameraRollIconStyle}>
                   <Icon
                     name="md-image"
                     size={25}
                     color={this.props.colors.listInputButton}
                   />
                 </Animated.View>
               </TouchableOpacity>
               <TouchableOpacity
                 onPress={this.openCamera}
                 activeOpacity={0.4}
                 disabled={!this.state.buttonsExpanded}
               >
                 <Animated.View style={this.cameraIconStyle}>
                   <FAIcon
                     name="camera"
                     size={20}
                     color={this.props.colors.listInputButton}
                   />
                 </Animated.View>
               </TouchableOpacity>
               {this.state.buttonsExpanded ? null : expandoButton}
             </View>
           </Animated.View>
           <ClearableTextInput
             allowImagePasteForThreadID={this.props.threadInfo.id}
             value={this.state.text}
             onChangeText={this.updateText}
             placeholder="Send a message..."
             placeholderTextColor={this.props.colors.listInputButton}
             multiline={true}
             style={this.props.styles.textInput}
             textInputRef={this.textInputRef}
             ref={this.clearableTextInputRef}
           />
           <Animated.View style={this.sendButtonContainerStyle}>
             <TouchableOpacity
               onPress={this.onSend}
               activeOpacity={0.4}
               style={this.props.styles.sendButton}
               disabled={trimMessage(this.state.text) === ''}
             >
               <Icon
                 name="md-send"
                 size={25}
                 style={this.props.styles.sendIcon}
                 color={threadColor}
               />
             </TouchableOpacity>
           </Animated.View>
         </View>
       </TouchableWithoutFeedback>
     );
   }
 
   textInputRef = (textInput: ?React.ElementRef<typeof TextInput>) => {
     this.textInput = textInput;
   };
 
   clearableTextInputRef = (clearableTextInput: ?ClearableTextInput) => {
     this.clearableTextInput = clearableTextInput;
   };
 
   updateText = (text: string) => {
     this.setState({ text });
     this.saveDraft(text);
   };
 
   saveDraft = _throttle((text: string) => {
     this.props.dispatch({
       type: saveDraftActionType,
       payload: {
         key: draftKeyFromThreadID(this.props.threadInfo.id),
         draft: text,
       },
     });
   }, 400);
 
   focusAndUpdateText = (text: string) => {
     const currentText = this.state.text;
     if (!currentText.startsWith(text)) {
       const prependedText = text.concat(currentText);
       this.updateText(prependedText);
       this.immediatelyShowSendButton();
       this.immediatelyHideButtons();
     }
     invariant(this.textInput, 'textInput should be set in focusAndUpdateText');
     this.textInput.focus();
   };
 
   getServerThreadID = async () => {
     if (this.newThreadID) {
       return this.newThreadID;
     }
     const { threadInfo } = this.props;
     if (!threadIsPending(threadInfo.id)) {
       return threadInfo.id;
     }
 
     const otherMemberIDs = getPendingThreadOtherUsers(threadInfo);
     try {
       let resultPromise;
       if (threadInfo.type !== threadTypes.SIDEBAR) {
+        invariant(
+          otherMemberIDs.length > 0,
+          'otherMemberIDs should not be empty for threads',
+        );
         resultPromise = this.props.newThread({
           type: pendingThreadType(otherMemberIDs.length),
           initialMemberIDs: otherMemberIDs,
           color: threadInfo.color,
         });
       } else {
         const sourceMessageID = this.props.route.params.sidebarSourceMessageID;
         invariant(
           sourceMessageID,
-          'sourceMessageID should be set getServerThreadID for sidebar',
+          'sourceMessageID should be set in getServerThreadID for sidebar',
         );
 
         resultPromise = this.props.newThread({
           type: threadTypes.SIDEBAR,
           initialMemberIDs: otherMemberIDs,
           color: threadInfo.color,
           sourceMessageID,
           parentThreadID: threadInfo.parentThreadID,
           name: threadInfo.name,
         });
       }
       this.props.dispatchActionPromise(newThreadActionTypes, resultPromise);
       const { newThreadID } = await resultPromise;
       this.newThreadID = newThreadID;
       return newThreadID;
     } catch (e) {
       Alert.alert('Unknown error', 'Uhh... try again?', [{ text: 'OK' }], {
         cancelable: false,
       });
     }
     return undefined;
   };
 
   onSend = async () => {
     if (!trimMessage(this.state.text)) {
       return;
     }
     this.updateSendButton('');
 
     const { clearableTextInput } = this;
     invariant(
       clearableTextInput,
       'clearableTextInput should be sent in onSend',
     );
     let text = await clearableTextInput.getValueAndReset();
     text = trimMessage(text);
     if (!text) {
       return;
     }
 
     const localID = `local${this.props.nextLocalID}`;
     const creatorID = this.props.viewerID;
     const threadID = await this.getServerThreadID();
     invariant(creatorID, 'should have viewer ID in order to send a message');
     invariant(
       this.props.inputState,
       'inputState should be set in ChatInputBar.onSend',
     );
 
     if (threadID) {
       this.props.inputState.sendTextMessage({
         type: messageTypes.TEXT,
         localID,
         threadID,
         text,
         creatorID,
         time: Date.now(),
       });
     }
   };
 
   onPressJoin = () => {
     this.props.dispatchActionPromise(joinThreadActionTypes, this.joinAction());
   };
 
   async joinAction() {
     const query = this.props.calendarQuery();
     return await this.props.joinThread({
       threadID: this.props.threadInfo.id,
       calendarQuery: {
         startDate: query.startDate,
         endDate: query.endDate,
         filters: [
           ...query.filters,
           { type: 'threads', threadIDs: [this.props.threadInfo.id] },
         ],
       },
     });
   }
 
   expandButtons = () => {
     if (this.state.buttonsExpanded) {
       return;
     }
     this.targetExpandoButtonsOpen.setValue(1);
     this.setState({ buttonsExpanded: true });
   };
 
   hideButtons() {
     if (
       ChatInputBar.mediaGalleryOpen(this.props) ||
       !this.systemKeyboardShowing ||
       !this.state.buttonsExpanded
     ) {
       return;
     }
     this.targetExpandoButtonsOpen.setValue(0);
     this.setState({ buttonsExpanded: false });
   }
 
   immediatelyHideButtons() {
     this.expandoButtonsOpen.setValue(0);
     this.targetExpandoButtonsOpen.setValue(0);
     this.setState({ buttonsExpanded: false });
   }
 
   openCamera = async () => {
     this.dismissKeyboard();
     this.props.navigation.navigate({
       name: CameraModalRouteName,
       params: {
         presentedFrom: this.props.route.key,
         threadID: this.props.threadInfo.id,
       },
     });
   };
 
   showMediaGallery = () => {
     const { keyboardState } = this.props;
     invariant(keyboardState, 'keyboardState should be initialized');
     keyboardState.showMediaGallery(this.props.threadInfo.id);
   };
 
   dismissKeyboard = () => {
     const { keyboardState } = this.props;
     keyboardState && keyboardState.dismissKeyboard();
   };
 }
 
 const unboundStyles = {
   cameraIcon: {
     paddingBottom: Platform.OS === 'android' ? 11 : 10,
     paddingRight: 3,
   },
   cameraRollIcon: {
     paddingBottom: Platform.OS === 'android' ? 8 : 7,
     paddingRight: 8,
   },
   container: {
     backgroundColor: 'listBackground',
   },
   expandButton: {
     bottom: 0,
     position: 'absolute',
     right: 0,
   },
   expandIcon: {
     paddingBottom: Platform.OS === 'android' ? 12 : 10,
   },
   expandoButtons: {
     alignSelf: 'flex-end',
   },
   explanation: {
     color: 'listBackgroundSecondaryLabel',
     paddingBottom: 4,
     paddingTop: 1,
     textAlign: 'center',
   },
   innerExpandoButtons: {
     alignItems: 'flex-end',
     alignSelf: 'flex-end',
     flexDirection: 'row',
   },
   inputContainer: {
     flexDirection: 'row',
   },
   joinButton: {
     backgroundColor: 'mintButton',
     borderRadius: 5,
     flex: 1,
     justifyContent: 'center',
     marginHorizontal: 12,
     marginVertical: 3,
     paddingBottom: 5,
     paddingTop: 3,
   },
   joinButtonContainer: {
     flexDirection: 'row',
     height: 36,
   },
   joinButtonText: {
     color: 'listBackground',
     fontSize: 20,
     textAlign: 'center',
   },
   joinThreadLoadingIndicator: {
     paddingVertical: 2,
   },
   sendButton: {
     position: 'absolute',
     bottom: Platform.OS === 'android' ? 4 : 3,
     left: 0,
   },
   sendIcon: {
     paddingLeft: 9,
     paddingRight: 8,
     paddingVertical: 5,
   },
   textInput: {
     backgroundColor: 'listInputBackground',
     borderRadius: 10,
     color: 'listForegroundLabel',
     fontSize: 16,
     marginLeft: 4,
     marginVertical: 5,
     maxHeight: 250,
     paddingHorizontal: 10,
     paddingVertical: 5,
   },
 };
 
 const joinThreadLoadingStatusSelector = createLoadingStatusSelector(
   joinThreadActionTypes,
 );
 
 export default React.memo<BaseProps>(function ConnectedChatInputBar(
   props: BaseProps,
 ) {
   const inputState = React.useContext(InputStateContext);
   const keyboardState = React.useContext(KeyboardContext);
   const navContext = React.useContext(NavContext);
 
   const styles = useStyles(unboundStyles);
   const colors = useColors();
 
   const isActive = React.useMemo(
     () => props.threadInfo.id === activeThreadSelector(navContext),
     [props.threadInfo.id, navContext],
   );
 
   const draftKey = draftKeyFromThreadID(props.threadInfo.id);
   const draft = useSelector((state) => state.drafts[draftKey] || '');
 
   const viewerID = useSelector(
     (state) => state.currentUserInfo && state.currentUserInfo.id,
   );
   const joinThreadLoadingStatus = useSelector(joinThreadLoadingStatusSelector);
   const calendarQuery = useSelector((state) =>
     nonThreadCalendarQuery({
       redux: state,
       navContext,
     }),
   );
   const nextLocalID = useSelector((state) => state.nextLocalID);
   const userInfos = useSelector((state) => state.userStore.userInfos);
 
   const dispatch = useDispatch();
   const dispatchActionPromise = useDispatchActionPromise();
   const callJoinThread = useServerCall(joinThread);
   const callNewThread = useServerCall(newThread);
 
   const imagePastedCallback = React.useCallback(
     (imagePastedEvent) => {
       if (props.threadInfo.id !== imagePastedEvent['threadID']) {
         return;
       }
       const pastedImage: PhotoPaste = {
         step: 'photo_paste',
         dimensions: {
           height: imagePastedEvent.height,
           width: imagePastedEvent.width,
         },
         filename: imagePastedEvent.fileName,
         uri: 'file://' + imagePastedEvent.filePath,
         selectTime: 0,
         sendTime: 0,
         retries: 0,
       };
       props.navigation.navigate({
         name: ImagePasteModalRouteName,
         params: {
           imagePasteStagingInfo: pastedImage,
           threadID: props.threadInfo.id,
         },
       });
     },
     [props.navigation, props.threadInfo.id],
   );
 
   React.useEffect(() => {
     const imagePasteListener = NativeAppEventEmitter.addListener(
       'imagePasted',
       imagePastedCallback,
     );
     return () => imagePasteListener.remove();
   }, [imagePastedCallback]);
 
   return (
     <ChatInputBar
       {...props}
       viewerID={viewerID}
       draft={draft}
       joinThreadLoadingStatus={joinThreadLoadingStatus}
       calendarQuery={calendarQuery}
       nextLocalID={nextLocalID}
       userInfos={userInfos}
       colors={colors}
       styles={styles}
       isActive={isActive}
       keyboardState={keyboardState}
       dispatch={dispatch}
       dispatchActionPromise={dispatchActionPromise}
       joinThread={callJoinThread}
       inputState={inputState}
       newThread={callNewThread}
     />
   );
 });
diff --git a/server/src/creators/thread-creator.js b/server/src/creators/thread-creator.js
index aef03ab06..d0b6bbe86 100644
--- a/server/src/creators/thread-creator.js
+++ b/server/src/creators/thread-creator.js
@@ -1,482 +1,507 @@
 // @flow
 
 import invariant from 'invariant';
 
 import bots from 'lib/facts/bots';
 import { relationshipBlockedInEitherDirection } from 'lib/shared/relationship-utils';
 import {
   generatePendingThreadColor,
   generateRandomColor,
 } from 'lib/shared/thread-utils';
 import { hasMinCodeVersion } from 'lib/shared/version-utils';
 import type { Shape } from 'lib/types/core';
 import { messageTypes } from 'lib/types/message-types';
 import { userRelationshipStatus } from 'lib/types/relationship-types';
 import {
   type NewThreadRequest,
   type NewThreadResponse,
   threadTypes,
   threadPermissions,
 } from 'lib/types/thread-types';
 import { ServerError } from 'lib/utils/errors';
 import { promiseAll } from 'lib/utils/promises';
 
 import { dbQuery, SQL } from '../database/database';
 import { fetchMessageInfoByID } from '../fetchers/message-fetchers';
 import { fetchThreadInfos } from '../fetchers/thread-fetchers';
 import { checkThreadPermission } from '../fetchers/thread-permission-fetchers';
 import { fetchKnownUserInfos } from '../fetchers/user-fetchers';
 import type { Viewer } from '../session/viewer';
 import {
   changeRole,
   recalculateAllPermissions,
   commitMembershipChangeset,
   setJoinsToUnread,
   getRelationshipRowsForUsers,
   getParentThreadRelationshipRowsForNewUsers,
 } from '../updaters/thread-permission-updaters';
 import createIDs from './id-creator';
 import createMessages from './message-creator';
 import { createInitialRolesForNewThread } from './role-creator';
 import type { UpdatesForCurrentSession } from './update-creator';
 
 const { squadbot } = bots;
 
 type CreateThreadOptions = Shape<{|
   +forceAddMembers: boolean,
   +updatesForCurrentSession: UpdatesForCurrentSession,
+  +silentlyFailMembers: boolean,
 |}>;
 
 // If forceAddMembers is set, we will allow the viewer to add random users who
 // they aren't friends with. We will only fail if the viewer is trying to add
 // somebody who they have blocked or has blocked them. On the other hand, if
 // forceAddMembers is not set, we will fail if the viewer tries to add somebody
 // who they aren't friends with and doesn't have a membership row with a
 // nonnegative role for the parent thread.
 async function createThread(
   viewer: Viewer,
   request: NewThreadRequest,
   options?: CreateThreadOptions,
 ): Promise<NewThreadResponse> {
   if (!viewer.loggedIn) {
     throw new ServerError('not_logged_in');
   }
 
   const forceAddMembers = options?.forceAddMembers ?? false;
   const updatesForCurrentSession =
     options?.updatesForCurrentSession ?? 'return';
+  const silentlyFailMembers = options?.silentlyFailMembers ?? false;
 
   const threadType = request.type;
   const shouldCreateRelationships =
     forceAddMembers || threadType === threadTypes.PERSONAL;
   const parentThreadID = request.parentThreadID ? request.parentThreadID : null;
-  const initialMemberIDs =
+  const initialMemberIDsFromRequest =
     request.initialMemberIDs && request.initialMemberIDs.length > 0
       ? request.initialMemberIDs
       : null;
   const ghostMemberIDs =
     request.ghostMemberIDs && request.ghostMemberIDs.length > 0
       ? request.ghostMemberIDs
       : null;
 
+  const sourceMessageID = request.sourceMessageID
+    ? request.sourceMessageID
+    : null;
+  invariant(
+    threadType !== threadTypes.SIDEBAR || sourceMessageID,
+    'sourceMessageID should be set for sidebar',
+  );
+
   if (
     threadType !== threadTypes.CHAT_SECRET &&
     threadType !== threadTypes.PERSONAL &&
     threadType !== threadTypes.PRIVATE &&
     !parentThreadID
   ) {
     throw new ServerError('invalid_parameters');
   }
 
   if (
     threadType === threadTypes.PERSONAL &&
     (request.initialMemberIDs?.length !== 1 || parentThreadID)
   ) {
     throw new ServerError('invalid_parameters');
   }
 
   const checkPromises = {};
   if (parentThreadID) {
     checkPromises.parentThreadFetch = fetchThreadInfos(
       viewer,
       SQL`t.id = ${parentThreadID}`,
     );
     checkPromises.hasParentPermission = checkThreadPermission(
       viewer,
       parentThreadID,
       threadType === threadTypes.SIDEBAR
         ? threadPermissions.CREATE_SIDEBARS
         : threadPermissions.CREATE_SUBTHREADS,
     );
   }
 
   const memberIDs = [];
-  if (initialMemberIDs) {
-    memberIDs.push(...initialMemberIDs);
+  if (initialMemberIDsFromRequest) {
+    memberIDs.push(...initialMemberIDsFromRequest);
   }
   if (ghostMemberIDs) {
     memberIDs.push(...ghostMemberIDs);
   }
 
-  if (initialMemberIDs || ghostMemberIDs) {
+  if (initialMemberIDsFromRequest || ghostMemberIDs) {
     checkPromises.fetchMemberIDs = fetchKnownUserInfos(viewer, memberIDs);
   }
 
+  if (sourceMessageID) {
+    checkPromises.sourceMessage = fetchMessageInfoByID(viewer, sourceMessageID);
+  }
+
   const {
     parentThreadFetch,
     hasParentPermission,
     fetchMemberIDs,
+    sourceMessage,
   } = await promiseAll(checkPromises);
 
   let parentThreadMembers;
   if (parentThreadID) {
     invariant(parentThreadFetch, 'parentThreadFetch should be set');
     const parentThreadInfo = parentThreadFetch.threadInfos[parentThreadID];
     if (!hasParentPermission) {
       throw new ServerError('invalid_credentials');
     }
     parentThreadMembers = parentThreadInfo.members.map(
       (userInfo) => userInfo.id,
     );
   }
 
   const viewerNeedsRelationshipsWith = [];
+  const silencedMemberIDs = new Set();
   if (fetchMemberIDs) {
-    invariant(initialMemberIDs || ghostMemberIDs, 'should be set');
+    invariant(initialMemberIDsFromRequest || ghostMemberIDs, 'should be set');
     for (const memberID of memberIDs) {
       const member = fetchMemberIDs[memberID];
       if (
         !member &&
         shouldCreateRelationships &&
         (threadType !== threadTypes.SIDEBAR ||
           parentThreadMembers?.includes(memberID))
       ) {
         viewerNeedsRelationshipsWith.push(memberID);
         continue;
+      } else if (!member && silentlyFailMembers) {
+        silencedMemberIDs.add(memberID);
+        continue;
       } else if (!member) {
         throw new ServerError('invalid_credentials');
       }
+
       const { relationshipStatus } = member;
+      const memberRelationshipHasBlock = !!(
+        relationshipStatus &&
+        relationshipBlockedInEitherDirection(relationshipStatus)
+      );
       if (
         relationshipStatus === userRelationshipStatus.FRIEND &&
         threadType !== threadTypes.SIDEBAR
       ) {
         continue;
-      } else if (
-        relationshipStatus &&
-        relationshipBlockedInEitherDirection(relationshipStatus)
-      ) {
+      } else if (memberRelationshipHasBlock && silentlyFailMembers) {
+        silencedMemberIDs.add(memberID);
+      } else if (memberRelationshipHasBlock) {
         throw new ServerError('invalid_credentials');
       } else if (
         parentThreadMembers &&
         parentThreadMembers.includes(memberID)
       ) {
         continue;
+      } else if (!shouldCreateRelationships && silentlyFailMembers) {
+        silencedMemberIDs.add(memberID);
       } else if (!shouldCreateRelationships) {
         throw new ServerError('invalid_credentials');
       }
     }
   }
 
+  const filteredInitialMemberIDs: ?$ReadOnlyArray<string> = initialMemberIDsFromRequest?.filter(
+    (id) => !silencedMemberIDs.has(id),
+  );
+  const initialMemberIDs =
+    filteredInitialMemberIDs && filteredInitialMemberIDs.length > 0
+      ? filteredInitialMemberIDs
+      : null;
+
   const [id] = await createIDs('threads', 1);
   const newRoles = await createInitialRolesForNewThread(id, threadType);
 
   const name = request.name ? request.name : null;
   const description = request.description ? request.description : null;
   let color = request.color
     ? request.color.toLowerCase()
     : generateRandomColor();
   if (threadType === threadTypes.PERSONAL) {
     color = generatePendingThreadColor(
       request.initialMemberIDs ?? [],
       viewer.id,
     );
   }
-  const sourceMessageID = request.sourceMessageID
-    ? request.sourceMessageID
-    : null;
-  invariant(
-    threadType !== threadTypes.SIDEBAR || sourceMessageID,
-    'sourceMessageID should be set for sidebar',
-  );
+
   const time = Date.now();
 
   const row = [
     id,
     threadType,
     name,
     description,
     viewer.userID,
     time,
     color,
     parentThreadID,
     newRoles.default.id,
     sourceMessageID,
   ];
   if (threadType === threadTypes.PERSONAL) {
     const otherMemberID = initialMemberIDs?.[0];
     invariant(
       otherMemberID,
       'Other member id should be set for a PERSONAL thread',
     );
     const query = SQL`
       INSERT INTO threads(id, type, name, description, creator,
         creation_time, color, parent_thread_id, default_role, source_message)
       SELECT ${row}
       WHERE NOT EXISTS (
         SELECT * 
         FROM threads t
         INNER JOIN memberships m1 
           ON m1.thread = t.id AND m1.user = ${viewer.userID}
         INNER JOIN memberships m2
           ON m2.thread = t.id AND m2.user = ${otherMemberID}
         WHERE t.type = ${threadTypes.PERSONAL}
           AND m1.role != -1
           AND m2.role != -1
       )
     `;
     const [result] = await dbQuery(query);
 
     if (result.affectedRows === 0) {
       const personalThreadQuery = SQL`
         SELECT t.id 
         FROM threads t
         INNER JOIN memberships m1 
           ON m1.thread = t.id AND m1.user = ${viewer.userID}
         INNER JOIN memberships m2
           ON m2.thread = t.id AND m2.user = ${otherMemberID}
         WHERE t.type = ${threadTypes.PERSONAL}
           AND m1.role != -1
           AND m2.role != -1
       `;
       const deleteRoles = SQL`
         DELETE FROM roles
         WHERE id IN (${newRoles.default.id}, ${newRoles.creator.id})
       `;
       const deleteIDs = SQL`
         DELETE FROM ids
         WHERE id IN (${id}, ${newRoles.default.id}, ${newRoles.creator.id})
       `;
       const [[personalThreadResult]] = await Promise.all([
         dbQuery(personalThreadQuery),
         dbQuery(deleteRoles),
         dbQuery(deleteIDs),
       ]);
       invariant(
         personalThreadResult.length > 0,
         'PERSONAL thread should exist',
       );
       const personalThreadID = personalThreadResult[0].id.toString();
 
       return {
         newThreadID: personalThreadID,
         updatesResult: {
           newUpdates: [],
         },
         userInfos: {},
         newMessageInfos: [],
       };
     }
   } else {
     const query = SQL`
       INSERT INTO threads(id, type, name, description, creator,
         creation_time, color, parent_thread_id, default_role, source_message)
       VALUES ${[row]}
     `;
     await dbQuery(query);
   }
 
   const [
     creatorChangeset,
     initialMembersChangeset,
     ghostMembersChangeset,
     recalculatePermissionsChangeset,
   ] = await Promise.all([
     changeRole(id, [viewer.userID], newRoles.creator.id),
     initialMemberIDs ? changeRole(id, initialMemberIDs, null) : undefined,
     ghostMemberIDs ? changeRole(id, ghostMemberIDs, -1) : undefined,
     recalculateAllPermissions(id, threadType),
   ]);
 
   if (!creatorChangeset) {
     throw new ServerError('unknown_error');
   }
   const {
     membershipRows: creatorMembershipRows,
     relationshipRows: creatorRelationshipRows,
   } = creatorChangeset;
 
   const {
     membershipRows: recalculateMembershipRows,
     relationshipRows: recalculateRelationshipRows,
   } = recalculatePermissionsChangeset;
 
   const membershipRows = [
     ...creatorMembershipRows,
     ...recalculateMembershipRows,
   ];
   const relationshipRows = [
     ...creatorRelationshipRows,
     ...recalculateRelationshipRows,
   ];
   if (initialMemberIDs || ghostMemberIDs) {
     if (!initialMembersChangeset && !ghostMembersChangeset) {
       throw new ServerError('unknown_error');
     }
     relationshipRows.push(
       ...getRelationshipRowsForUsers(
         viewer.userID,
         viewerNeedsRelationshipsWith,
       ),
     );
     const membersMembershipRows = [];
     const membersRelationshipRows = [];
     if (initialMembersChangeset) {
       const {
         membershipRows: initialMembersMembershipRows,
         relationshipRows: initialMembersRelationshipRows,
       } = initialMembersChangeset;
       membersMembershipRows.push(...initialMembersMembershipRows);
       membersRelationshipRows.push(...initialMembersRelationshipRows);
     }
 
     if (ghostMembersChangeset) {
       const {
         membershipRows: ghostMembersMembershipRows,
         relationshipRows: ghostMembersRelationshipRows,
       } = ghostMembersChangeset;
       membersMembershipRows.push(...ghostMembersMembershipRows);
       membersRelationshipRows.push(...ghostMembersRelationshipRows);
     }
 
     const memberAndCreatorIDs = [...memberIDs, viewer.userID];
     const parentRelationshipRows = getParentThreadRelationshipRowsForNewUsers(
       id,
       recalculateMembershipRows,
       memberAndCreatorIDs,
     );
     membershipRows.push(...membersMembershipRows);
     relationshipRows.push(
       ...membersRelationshipRows,
       ...parentRelationshipRows,
     );
   }
 
   setJoinsToUnread(membershipRows, viewer.userID, id);
 
   const changeset = { membershipRows, relationshipRows };
   const {
     threadInfos,
     viewerUpdates,
     userInfos,
   } = await commitMembershipChangeset(viewer, changeset, {
     updatesForCurrentSession,
   });
 
   const initialMemberAndCreatorIDs = initialMemberIDs
     ? [...initialMemberIDs, viewer.userID]
     : [viewer.userID];
   const messageDatas = [];
   if (threadType !== threadTypes.SIDEBAR) {
     messageDatas.push({
       type: messageTypes.CREATE_THREAD,
       threadID: id,
       creatorID: viewer.userID,
       time,
       initialThreadState: {
         type: threadType,
         name,
         parentThreadID,
         color,
         memberIDs: initialMemberAndCreatorIDs,
       },
     });
   } else {
     invariant(parentThreadID, 'parentThreadID should be set for sidebar');
-    invariant(sourceMessageID, 'sourceMessageID should be set for sidebar');
-    const sourceMessage = await fetchMessageInfoByID(viewer, sourceMessageID);
     if (!sourceMessage || sourceMessage.type === messageTypes.SIDEBAR_SOURCE) {
       throw new ServerError('invalid_parameters');
     }
 
     messageDatas.push(
       {
         type: messageTypes.CREATE_SIDEBAR,
         threadID: id,
         creatorID: viewer.userID,
         time,
         sourceMessageAuthorID: sourceMessage.creatorID,
         initialThreadState: {
           name,
           parentThreadID,
           color,
           memberIDs: initialMemberAndCreatorIDs,
         },
       },
       {
         type: messageTypes.SIDEBAR_SOURCE,
         threadID: id,
         creatorID: viewer.userID,
         time,
         sourceMessage,
       },
     );
   }
 
   if (parentThreadID && threadType !== threadTypes.SIDEBAR) {
     messageDatas.push({
       type: messageTypes.CREATE_SUB_THREAD,
       threadID: parentThreadID,
       creatorID: viewer.userID,
       time,
       childThreadID: id,
     });
   }
   const newMessageInfos = await createMessages(
     viewer,
     messageDatas,
     updatesForCurrentSession,
   );
 
   if (hasMinCodeVersion(viewer.platformDetails, 62)) {
     return {
       newThreadID: id,
       updatesResult: {
         newUpdates: viewerUpdates,
       },
       userInfos,
       newMessageInfos,
     };
   }
 
   return {
     newThreadInfo: threadInfos[id],
     updatesResult: {
       newUpdates: viewerUpdates,
     },
     userInfos,
     newMessageInfos,
   };
 }
 
 function createPrivateThread(
   viewer: Viewer,
   username: string,
 ): Promise<NewThreadResponse> {
   return createThread(
     viewer,
     {
       type: threadTypes.PRIVATE,
       name: username,
       description:
         'This is your private thread, ' +
         'where you can set reminders and jot notes in private!',
       ghostMemberIDs: [squadbot.userID],
     },
     {
       forceAddMembers: true,
     },
   );
 }
 
 export { createThread, createPrivateThread };
diff --git a/server/src/responders/thread-responders.js b/server/src/responders/thread-responders.js
index f8fc3271a..c5430806c 100644
--- a/server/src/responders/thread-responders.js
+++ b/server/src/responders/thread-responders.js
@@ -1,182 +1,185 @@
 // @flow
 
 import t from 'tcomb';
 
 import {
   type ThreadDeletionRequest,
   type RoleChangeRequest,
   type ChangeThreadSettingsResult,
   type RemoveMembersRequest,
   type LeaveThreadRequest,
   type LeaveThreadResult,
   type UpdateThreadRequest,
   type NewThreadRequest,
   type NewThreadResponse,
   type ServerThreadJoinRequest,
   type ThreadJoinResult,
   threadTypes,
 } from 'lib/types/thread-types';
 import { values } from 'lib/utils/objects';
 
 import { createThread } from '../creators/thread-creator';
 import { deleteThread } from '../deleters/thread-deleters';
 import type { Viewer } from '../session/viewer';
 import {
   updateRole,
   removeMembers,
   leaveThread,
   updateThread,
   joinThread,
 } from '../updaters/thread-updaters';
 import {
   validateInput,
   tShape,
   tNumEnum,
   tColor,
   tPassword,
 } from '../utils/validation-utils';
 import {
   entryQueryInputValidator,
   verifyCalendarQueryThreadIDs,
 } from './entry-responders';
 
 const threadDeletionRequestInputValidator = tShape({
   threadID: t.String,
   accountPassword: tPassword,
 });
 
 async function threadDeletionResponder(
   viewer: Viewer,
   input: any,
 ): Promise<LeaveThreadResult> {
   const request: ThreadDeletionRequest = input;
   await validateInput(viewer, threadDeletionRequestInputValidator, request);
   return await deleteThread(viewer, request);
 }
 
 const roleChangeRequestInputValidator = tShape({
   threadID: t.String,
   memberIDs: t.list(t.String),
   role: t.refinement(t.String, (str) => {
     const int = parseInt(str, 10);
     return int == str && int > 0;
   }),
 });
 
 async function roleUpdateResponder(
   viewer: Viewer,
   input: any,
 ): Promise<ChangeThreadSettingsResult> {
   const request: RoleChangeRequest = input;
   await validateInput(viewer, roleChangeRequestInputValidator, request);
   return await updateRole(viewer, request);
 }
 
 const removeMembersRequestInputValidator = tShape({
   threadID: t.String,
   memberIDs: t.list(t.String),
 });
 
 async function memberRemovalResponder(
   viewer: Viewer,
   input: any,
 ): Promise<ChangeThreadSettingsResult> {
   const request: RemoveMembersRequest = input;
   await validateInput(viewer, removeMembersRequestInputValidator, request);
   return await removeMembers(viewer, request);
 }
 
 const leaveThreadRequestInputValidator = tShape({
   threadID: t.String,
 });
 
 async function threadLeaveResponder(
   viewer: Viewer,
   input: any,
 ): Promise<LeaveThreadResult> {
   const request: LeaveThreadRequest = input;
   await validateInput(viewer, leaveThreadRequestInputValidator, request);
   return await leaveThread(viewer, request);
 }
 
 const updateThreadRequestInputValidator = tShape({
   threadID: t.String,
   changes: tShape({
     type: t.maybe(tNumEnum(values(threadTypes))),
     name: t.maybe(t.String),
     description: t.maybe(t.String),
     color: t.maybe(tColor),
     parentThreadID: t.maybe(t.String),
     newMemberIDs: t.maybe(t.list(t.String)),
   }),
   accountPassword: t.maybe(tPassword),
 });
 
 async function threadUpdateResponder(
   viewer: Viewer,
   input: any,
 ): Promise<ChangeThreadSettingsResult> {
   const request: UpdateThreadRequest = input;
   await validateInput(viewer, updateThreadRequestInputValidator, request);
   return await updateThread(viewer, request);
 }
 
 const threadRequestValidationShape = {
   name: t.maybe(t.String),
   description: t.maybe(t.String),
   color: t.maybe(tColor),
   parentThreadID: t.maybe(t.String),
   initialMemberIDs: t.maybe(t.list(t.String)),
 };
 const newThreadRequestInputValidator = t.union([
   tShape({
     type: tNumEnum([threadTypes.SIDEBAR]),
     sourceMessageID: t.String,
     ...threadRequestValidationShape,
   }),
   tShape({
     type: tNumEnum([
       threadTypes.CHAT_NESTED_OPEN,
       threadTypes.CHAT_SECRET,
       threadTypes.PERSONAL,
     ]),
     ...threadRequestValidationShape,
   }),
 ]);
 async function threadCreationResponder(
   viewer: Viewer,
   input: any,
 ): Promise<NewThreadResponse> {
   const request: NewThreadRequest = input;
   await validateInput(viewer, newThreadRequestInputValidator, request);
-  return await createThread(viewer, request);
+
+  return await createThread(viewer, request, {
+    silentlyFailMembers: request.type === threadTypes.SIDEBAR,
+  });
 }
 
 const joinThreadRequestInputValidator = tShape({
   threadID: t.String,
   calendarQuery: t.maybe(entryQueryInputValidator),
 });
 async function threadJoinResponder(
   viewer: Viewer,
   input: any,
 ): Promise<ThreadJoinResult> {
   const request: ServerThreadJoinRequest = input;
   await validateInput(viewer, joinThreadRequestInputValidator, request);
 
   if (request.calendarQuery) {
     await verifyCalendarQueryThreadIDs(request.calendarQuery);
   }
 
   return await joinThread(viewer, request);
 }
 
 export {
   threadDeletionResponder,
   roleUpdateResponder,
   memberRemovalResponder,
   threadLeaveResponder,
   threadUpdateResponder,
   threadCreationResponder,
   threadJoinResponder,
   newThreadRequestInputValidator,
 };