diff --git a/res/css/_components.scss b/res/css/_components.scss
index 2a34cd1734..006bac09c9 100644
--- a/res/css/_components.scss
+++ b/res/css/_components.scss
@@ -107,6 +107,7 @@
 @import "./views/elements/_AddressTile.scss";
 @import "./views/elements/_DesktopBuildsNotice.scss";
 @import "./views/elements/_DirectorySearchBox.scss";
+@import "./views/elements/_DesktopCapturerSourcePicker.scss";
 @import "./views/elements/_Dropdown.scss";
 @import "./views/elements/_EditableItemList.scss";
 @import "./views/elements/_ErrorBoundary.scss";
diff --git a/res/css/structures/_LeftPanelWidget.scss b/res/css/structures/_LeftPanelWidget.scss
index 4df651d7b6..6e2d99bb37 100644
--- a/res/css/structures/_LeftPanelWidget.scss
+++ b/res/css/structures/_LeftPanelWidget.scss
@@ -134,7 +134,7 @@ limitations under the License.
             mask-position: center;
             mask-size: contain;
             mask-repeat: no-repeat;
-            mask-image: url('$(res)/img/feather-customised/widget/maximise.svg');
+            mask-image: url('$(res)/img/feather-customised/maximise.svg');
             background: $muted-fg-color;
         }
     }
diff --git a/res/css/structures/_RoomDirectory.scss b/res/css/structures/_RoomDirectory.scss
index 29e6fecd34..89cb21b7a6 100644
--- a/res/css/structures/_RoomDirectory.scss
+++ b/res/css/structures/_RoomDirectory.scss
@@ -64,28 +64,23 @@ limitations under the License.
 }
 
 .mx_RoomDirectory_table {
-    font-size: $font-12px;
     color: $primary-fg-color;
-    width: 100%;
+    display: grid;
+    font-size: $font-12px;
+    grid-template-columns: max-content auto max-content max-content max-content;
+    row-gap: 24px;
     text-align: left;
-    table-layout: fixed;
+    width: 100%;
 }
 
 .mx_RoomDirectory_roomAvatar {
-    width: 32px;
-    padding-right: 14px;
-    vertical-align: top;
-}
-
-.mx_RoomDirectory_roomDescription {
-    padding-bottom: 16px;
+    padding: 2px 14px 0 0;
 }
 
 .mx_RoomDirectory_roomMemberCount {
+    align-self: center;
     color: $light-fg-color;
-    width: 60px;
-    padding: 0 10px;
-    text-align: center;
+    padding: 3px 10px 0;
 
     &::before {
         background-color: $light-fg-color;
@@ -105,8 +100,7 @@ limitations under the License.
 }
 
 .mx_RoomDirectory_join, .mx_RoomDirectory_preview {
-    width: 80px;
-    text-align: center;
+    align-self: center;
     white-space: nowrap;
 }
 
diff --git a/res/css/views/elements/_DesktopCapturerSourcePicker.scss b/res/css/views/elements/_DesktopCapturerSourcePicker.scss
new file mode 100644
index 0000000000..69dde5925e
--- /dev/null
+++ b/res/css/views/elements/_DesktopCapturerSourcePicker.scss
@@ -0,0 +1,72 @@
+/*
+Copyright 2021 Šimon Brandner <simon.bra.ag@gmail.com>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+.mx_desktopCapturerSourcePicker {
+    overflow: hidden;
+}
+
+.mx_desktopCapturerSourcePicker_tabLabels {
+    display: flex;
+    padding: 0 0 8px 0;
+}
+
+.mx_desktopCapturerSourcePicker_tabLabel,
+.mx_desktopCapturerSourcePicker_tabLabel_selected {
+    width: 100%;
+    text-align: center;
+    border-radius: 8px;
+    padding: 8px 0;
+    font-size: $font-13px;
+}
+
+.mx_desktopCapturerSourcePicker_tabLabel_selected {
+    background-color: $tab-label-active-bg-color;
+    color: $tab-label-active-fg-color;
+}
+
+.mx_desktopCapturerSourcePicker_panel {
+    display: flex;
+    flex-wrap: wrap;
+    justify-content: center;
+    align-items: flex-start;
+    height: 500px;
+    overflow: overlay;
+}
+
+.mx_desktopCapturerSourcePicker_stream_button {
+    display: flex;
+    flex-direction: column;
+    margin: 8px;
+    border-radius: 4px;
+}
+
+.mx_desktopCapturerSourcePicker_stream_button:hover,
+.mx_desktopCapturerSourcePicker_stream_button:focus {
+    background: $roomtile-selected-bg-color;
+}
+
+.mx_desktopCapturerSourcePicker_stream_thumbnail {
+    margin: 4px;
+    width: 312px;
+}
+
+.mx_desktopCapturerSourcePicker_stream_name {
+    margin: 0 4px;
+    white-space: nowrap;
+    text-overflow: ellipsis;
+    overflow: hidden;
+    width: 312px;
+}
diff --git a/res/css/views/messages/_ViewSourceEvent.scss b/res/css/views/messages/_ViewSourceEvent.scss
index 076932ee97..66825030e0 100644
--- a/res/css/views/messages/_ViewSourceEvent.scss
+++ b/res/css/views/messages/_ViewSourceEvent.scss
@@ -35,13 +35,13 @@ limitations under the License.
         mask-size: auto 12px;
         visibility: hidden;
         background-color: $accent-color;
-        mask-image: url('$(res)/img/feather-customised/widget/maximise.svg');
+        mask-image: url('$(res)/img/feather-customised/maximise.svg');
     }
 
     &.mx_ViewSourceEvent_expanded .mx_ViewSourceEvent_toggle {
         mask-position: 0 bottom;
         margin-bottom: 7px;
-        mask-image: url('$(res)/img/feather-customised/widget/minimise.svg');
+        mask-image: url('$(res)/img/feather-customised/minimise.svg');
     }
 
     &:hover .mx_ViewSourceEvent_toggle {
diff --git a/res/css/views/rooms/_EventTile.scss b/res/css/views/rooms/_EventTile.scss
index 42d91b3eb5..da94f914f7 100644
--- a/res/css/views/rooms/_EventTile.scss
+++ b/res/css/views/rooms/_EventTile.scss
@@ -491,7 +491,6 @@ $left-gutter: 64px;
         // https://github.com/vector-im/vector-web/issues/754
         overflow-x: overlay;
         overflow-y: visible;
-        max-height: 30vh;
     }
 
     code {
@@ -500,6 +499,22 @@ $left-gutter: 64px;
     }
 }
 
+.mx_EventTile_lineNumbers {
+    float: left;
+    margin: 0 0.5em 0 -1.5em;
+    color: gray;
+}
+
+.mx_EventTile_lineNumber {
+    text-align: right;
+    display: block;
+    padding-left: 1em;
+}
+
+.mx_EventTile_collapsedCodeBlock {
+    max-height: 30vh;
+}
+
 .mx_EventTile:hover .mx_EventTile_body pre,
 .mx_EventTile.focus-visible:focus-within .mx_EventTile_body pre {
     border: 1px solid #e5e5e5; // deliberate constant as we're behind an invert filter
@@ -511,7 +526,7 @@ $left-gutter: 64px;
 }
 
 // Inserted adjacent to <pre> blocks, (See TextualBody)
-.mx_EventTile_copyButton {
+.mx_EventTile_button {
     position: absolute;
     display: inline-block;
     visibility: hidden;
@@ -520,12 +535,33 @@ $left-gutter: 64px;
     right: 6px;
     width: 19px;
     height: 19px;
-    mask-image: url($copy-button-url);
     background-color: $message-action-bar-fg-color;
 }
+.mx_EventTile_buttonBottom {
+    top: 31px;
+}
+.mx_EventTile_copyButton {
+    mask-image: url($copy-button-url);
+}
+.mx_EventTile_collapseButton {
+    mask-size: 75%;
+    mask-position: center;
+    mask-repeat: no-repeat;
+    mask-image: url($collapse-button-url);
+}
+.mx_EventTile_expandButton {
+    mask-size: 75%;
+    mask-position: center;
+    mask-repeat: no-repeat;
+    mask-image: url($expand-button-url);
+}
 
 .mx_EventTile_body .mx_EventTile_pre_container:focus-within .mx_EventTile_copyButton,
-.mx_EventTile_body .mx_EventTile_pre_container:hover .mx_EventTile_copyButton {
+.mx_EventTile_body .mx_EventTile_pre_container:hover .mx_EventTile_copyButton,
+.mx_EventTile_body .mx_EventTile_pre_container:focus-within .mx_EventTile_collapseButton,
+.mx_EventTile_body .mx_EventTile_pre_container:hover .mx_EventTile_collapseButton,
+.mx_EventTile_body .mx_EventTile_pre_container:focus-within .mx_EventTile_expandButton,
+.mx_EventTile_body .mx_EventTile_pre_container:hover .mx_EventTile_expandButton {
     visibility: visible;
 }
 
diff --git a/res/css/views/settings/_Notifications.scss b/res/css/views/settings/_Notifications.scss
index e6d09b9a2a..77a7bc5b68 100644
--- a/res/css/views/settings/_Notifications.scss
+++ b/res/css/views/settings/_Notifications.scss
@@ -64,6 +64,7 @@ limitations under the License.
 
 .mx_UserNotifSettings_notifTable {
     display: table;
+    position: relative;
 }
 
 .mx_UserNotifSettings_notifTable .mx_Spinner {
diff --git a/res/img/feather-customised/widget/maximise.svg b/res/img/feather-customised/maximise.svg
similarity index 100%
rename from res/img/feather-customised/widget/maximise.svg
rename to res/img/feather-customised/maximise.svg
diff --git a/res/img/feather-customised/widget/minimise.svg b/res/img/feather-customised/minimise.svg
similarity index 100%
rename from res/img/feather-customised/widget/minimise.svg
rename to res/img/feather-customised/minimise.svg
diff --git a/res/themes/legacy-light/css/_legacy-light.scss b/res/themes/legacy-light/css/_legacy-light.scss
index 085d6d7f10..a740ba155c 100644
--- a/res/themes/legacy-light/css/_legacy-light.scss
+++ b/res/themes/legacy-light/css/_legacy-light.scss
@@ -237,7 +237,8 @@ $event-redacted-border-color: #cccccc;
 $event-timestamp-color: #acacac;
 
 $copy-button-url: "$(res)/img/feather-customised/clipboard.svg";
-
+$collapse-button-url: "$(res)/img/feather-customised/minimise.svg";
+$expand-button-url: "$(res)/img/feather-customised/maximise.svg";
 
 // e2e
 $e2e-verified-color: #76cfa5; // N.B. *NOT* the same as $accent-color
diff --git a/res/themes/light/css/_light.scss b/res/themes/light/css/_light.scss
index 4cfeeae05e..1c89d83c01 100644
--- a/res/themes/light/css/_light.scss
+++ b/res/themes/light/css/_light.scss
@@ -237,6 +237,8 @@ $event-redacted-border-color: #cccccc;
 $event-timestamp-color: #acacac;
 
 $copy-button-url: "$(res)/img/feather-customised/clipboard.svg";
+$collapse-button-url: "$(res)/img/feather-customised/minimise.svg";
+$expand-button-url: "$(res)/img/feather-customised/maximise.svg";
 
 // e2e
 $e2e-verified-color: #76cfa5; // N.B. *NOT* the same as $accent-color
diff --git a/src/CallHandler.tsx b/src/CallHandler.tsx
index 9dee7594ea..a6d3534fa1 100644
--- a/src/CallHandler.tsx
+++ b/src/CallHandler.tsx
@@ -82,6 +82,7 @@ import CountlyAnalytics from "./CountlyAnalytics";
 import {UIFeature} from "./settings/UIFeature";
 import { CallError } from "matrix-js-sdk/src/webrtc/call";
 import { logger } from 'matrix-js-sdk/src/logger';
+import DesktopCapturerSourcePicker from "./components/views/elements/DesktopCapturerSourcePicker"
 import { Action } from './dispatcher/actions';
 import { roomForVirtualRoom, getOrCreateVirtualRoomForRoom } from './VoipUserMapper';
 import { addManagedHybridWidget, isManagedHybridWidgetEnabled } from './widgets/ManagedHybrid';
@@ -572,9 +573,17 @@ export default class CallHandler {
                 });
                 return;
             }
-            call.placeScreenSharingCall(remoteElement, localElement);
+
+            call.placeScreenSharingCall(
+                remoteElement,
+                localElement,
+                async () : Promise<DesktopCapturerSource> => {
+                    const {finished} = Modal.createDialog(DesktopCapturerSourcePicker);
+                    const [source] = await finished;
+                    return source;
+                });
         } else {
-            console.error("Unknown conf call type: %s", type);
+            console.error("Unknown conf call type: " + type);
         }
     }
 
@@ -608,7 +617,7 @@ export default class CallHandler {
 
                     const room = MatrixClientPeg.get().getRoom(payload.room_id);
                     if (!room) {
-                        console.error("Room %s does not exist.", payload.room_id);
+                        console.error(`Room ${payload.room_id} does not exist.`);
                         return;
                     }
 
@@ -619,7 +628,7 @@ export default class CallHandler {
                         });
                         return;
                     } else if (members.length === 2) {
-                        console.info("Place %s call in %s", payload.type, payload.room_id);
+                        console.info(`Place ${payload.type} call in ${payload.room_id}`);
 
                         this.placeCall(payload.room_id, payload.type, payload.local_element, payload.remote_element);
                     } else { // > 2
@@ -634,17 +643,17 @@ export default class CallHandler {
                 }
                 break;
             case 'place_conference_call':
-                console.info("Place conference call in %s", payload.room_id);
+                console.info("Place conference call in " + payload.room_id);
                 Analytics.trackEvent('voip', 'placeConferenceCall');
                 CountlyAnalytics.instance.trackStartCall(payload.room_id, payload.type === PlaceCallType.Video, true);
                 this.startCallApp(payload.room_id, payload.type);
                 break;
             case 'end_conference':
-                console.info("Terminating conference call in %s", payload.room_id);
+                console.info("Terminating conference call in " + payload.room_id);
                 this.terminateCallApp(payload.room_id);
                 break;
             case 'hangup_conference':
-                console.info("Leaving conference call in %s", payload.room_id);
+                console.info("Leaving conference call in "+ payload.room_id);
                 this.hangupCallApp(payload.room_id);
                 break;
             case 'incoming_call':
diff --git a/src/RoomNotifs.js b/src/RoomNotifs.js
index a86c521ac4..600655f635 100644
--- a/src/RoomNotifs.js
+++ b/src/RoomNotifs.js
@@ -202,12 +202,13 @@ function setRoomNotifsStateUnmuted(roomId, newState) {
 }
 
 function findOverrideMuteRule(roomId) {
-    if (!MatrixClientPeg.get().pushRules ||
-        !MatrixClientPeg.get().pushRules['global'] ||
-        !MatrixClientPeg.get().pushRules['global'].override) {
+    const cli = MatrixClientPeg.get();
+    if (!cli.pushRules ||
+        !cli.pushRules['global'] ||
+        !cli.pushRules['global'].override) {
         return null;
     }
-    for (const rule of MatrixClientPeg.get().pushRules['global'].override) {
+    for (const rule of cli.pushRules['global'].override) {
         if (isRuleForRoom(roomId, rule)) {
             if (isMuteRule(rule) && rule.enabled) {
                 return rule;
diff --git a/src/components/structures/MatrixChat.tsx b/src/components/structures/MatrixChat.tsx
index 8ed4b6cd11..5045e44182 100644
--- a/src/components/structures/MatrixChat.tsx
+++ b/src/components/structures/MatrixChat.tsx
@@ -755,6 +755,8 @@ export default class MatrixChat extends React.PureComponent<IProps, IState> {
                 break;
             case 'on_logged_in':
                 if (
+                    // Skip this handling for token login as that always calls onLoggedIn itself
+                    !this.tokenLogin &&
                     !Lifecycle.isSoftLogout() &&
                     this.state.view !== Views.LOGIN &&
                     this.state.view !== Views.REGISTER &&
@@ -1373,6 +1375,9 @@ export default class MatrixChat extends React.PureComponent<IProps, IState> {
         cli.on('Session.logged_out', function(errObj) {
             if (Lifecycle.isLoggingOut()) return;
 
+            // A modal might have been open when we were logged out by the server
+            Modal.closeCurrentModal('Session.logged_out');
+
             if (errObj.httpStatus === 401 && errObj.data && errObj.data['soft_logout']) {
                 console.warn("Soft logout issued by server - avoiding data deletion");
                 Lifecycle.softLogout();
@@ -1383,6 +1388,7 @@ export default class MatrixChat extends React.PureComponent<IProps, IState> {
                 title: _t('Signed Out'),
                 description: _t('For security, this session has been signed out. Please sign in again.'),
             });
+
             dis.dispatch({
                 action: 'logout',
             });
@@ -1652,10 +1658,16 @@ export default class MatrixChat extends React.PureComponent<IProps, IState> {
             // TODO: Handle encoded room/event IDs: https://github.com/vector-im/element-web/issues/9149
 
             let threepidInvite: IThreepidInvite;
+            // if we landed here from a 3PID invite, persist it
             if (params.signurl && params.email) {
                 threepidInvite = ThreepidInviteStore.instance
                     .storeInvite(roomString, params as IThreepidInviteWireFormat);
             }
+            // otherwise check that this room doesn't already have a known invite
+            if (!threepidInvite) {
+                const invites = ThreepidInviteStore.instance.getInvites();
+                threepidInvite = invites.find(invite => invite.roomId === roomString);
+            }
 
             // on our URLs there might be a ?via=matrix.org or similar to help
             // joins to the room succeed. We'll pass these through as an array
diff --git a/src/components/structures/MessagePanel.js b/src/components/structures/MessagePanel.js
index b8dae41ef8..371623642b 100644
--- a/src/components/structures/MessagePanel.js
+++ b/src/components/structures/MessagePanel.js
@@ -229,7 +229,7 @@ export default class MessagePanel extends React.Component {
 
     onAction = (payload) => {
         switch (payload.action) {
-            case "message_sent":
+            case "scroll_to_bottom":
                 this.scrollToBottom();
                 break;
         }
diff --git a/src/components/structures/RoomDirectory.js b/src/components/structures/RoomDirectory.js
index 9ddacaf829..7387e1aac0 100644
--- a/src/components/structures/RoomDirectory.js
+++ b/src/components/structures/RoomDirectory.js
@@ -477,7 +477,7 @@ export default class RoomDirectory extends React.Component {
         dis.dispatch(payload);
     }
 
-    getRow(room) {
+    createRoomCells(room) {
         const client = MatrixClientPeg.get();
         const clientRoom = client.getRoom(room.room_id);
         const hasJoinedRoom = clientRoom && clientRoom.getMyMembership() === "join";
@@ -523,31 +523,56 @@ export default class RoomDirectory extends React.Component {
                                 MatrixClientPeg.get().getHomeserverUrl(),
                                 room.avatar_url, 32, 32, "crop",
                             );
-        return (
-            <tr key={ room.room_id }
+        return [
+            <div key={ `${room.room_id}_avatar` }
                 onClick={(ev) => this.onRoomClicked(room, ev)}
                 // cancel onMouseDown otherwise shift-clicking highlights text
                 onMouseDown={(ev) => {ev.preventDefault();}}
+                className="mx_RoomDirectory_roomAvatar"
             >
-                <td className="mx_RoomDirectory_roomAvatar">
-                    <BaseAvatar width={32} height={32} resizeMethod='crop'
-                        name={ name } idName={ name }
-                        url={ avatarUrl } />
-                </td>
-                <td className="mx_RoomDirectory_roomDescription">
-                    <div className="mx_RoomDirectory_name">{ name }</div>&nbsp;
-                    <div className="mx_RoomDirectory_topic"
-                        onClick={ (ev) => { ev.stopPropagation(); } }
-                        dangerouslySetInnerHTML={{ __html: topic }} />
-                    <div className="mx_RoomDirectory_alias">{ get_display_alias_for_room(room) }</div>
-                </td>
-                <td className="mx_RoomDirectory_roomMemberCount">
-                    { room.num_joined_members }
-                </td>
-                <td className="mx_RoomDirectory_preview">{previewButton}</td>
-                <td className="mx_RoomDirectory_join">{joinOrViewButton}</td>
-            </tr>
-        );
+                <BaseAvatar width={32} height={32} resizeMethod='crop'
+                    name={ name } idName={ name }
+                    url={ avatarUrl }
+                />
+            </div>,
+            <div key={ `${room.room_id}_description` }
+                onClick={(ev) => this.onRoomClicked(room, ev)}
+                // cancel onMouseDown otherwise shift-clicking highlights text
+                onMouseDown={(ev) => {ev.preventDefault();}}
+                className="mx_RoomDirectory_roomDescription"
+            >
+                <div className="mx_RoomDirectory_name">{ name }</div>&nbsp;
+                <div className="mx_RoomDirectory_topic"
+                    onClick={ (ev) => { ev.stopPropagation(); } }
+                    dangerouslySetInnerHTML={{ __html: topic }}
+                />
+                <div className="mx_RoomDirectory_alias">{ get_display_alias_for_room(room) }</div>
+            </div>,
+            <div key={ `${room.room_id}_memberCount` }
+                onClick={(ev) => this.onRoomClicked(room, ev)}
+                // cancel onMouseDown otherwise shift-clicking highlights text
+                onMouseDown={(ev) => {ev.preventDefault();}}
+                className="mx_RoomDirectory_roomMemberCount"
+            >
+                { room.num_joined_members }
+            </div>,
+            <div key={ `${room.room_id}_preview` }
+                onClick={(ev) => this.onRoomClicked(room, ev)}
+                // cancel onMouseDown otherwise shift-clicking highlights text
+                onMouseDown={(ev) => {ev.preventDefault();}}
+                className="mx_RoomDirectory_preview"
+            >
+                {previewButton}
+            </div>,
+            <div key={ `${room.room_id}_join` }
+                onClick={(ev) => this.onRoomClicked(room, ev)}
+                // cancel onMouseDown otherwise shift-clicking highlights text
+                onMouseDown={(ev) => {ev.preventDefault();}}
+                className="mx_RoomDirectory_join"
+            >
+                {joinOrViewButton}
+            </div>,
+        ];
     }
 
     collectScrollPanel = (element) => {
@@ -606,7 +631,8 @@ export default class RoomDirectory extends React.Component {
         } else if (this.state.protocolsLoading) {
             content = <Loader />;
         } else {
-            const rows = (this.state.publicRooms || []).map(room => this.getRow(room));
+            const cells = (this.state.publicRooms || [])
+                .reduce((cells, room) => cells.concat(this.createRoomCells(room)), [],);
             // we still show the scrollpanel, at least for now, because
             // otherwise we don't fetch more because we don't get a fill
             // request from the scrollpanel because there isn't one
@@ -617,14 +643,12 @@ export default class RoomDirectory extends React.Component {
             }
 
             let scrollpanel_content;
-            if (rows.length === 0 && !this.state.loading) {
+            if (cells.length === 0 && !this.state.loading) {
                 scrollpanel_content = <i>{ _t('No rooms to show') }</i>;
             } else {
-                scrollpanel_content = <table className="mx_RoomDirectory_table">
-                    <tbody>
-                        { rows }
-                    </tbody>
-                </table>;
+                scrollpanel_content = <div className="mx_RoomDirectory_table">
+                    { cells }
+                </div>;
             }
             const ScrollPanel = sdk.getComponent("structures.ScrollPanel");
             content = <ScrollPanel ref={this.collectScrollPanel}
diff --git a/src/components/views/elements/DesktopCapturerSourcePicker.tsx b/src/components/views/elements/DesktopCapturerSourcePicker.tsx
new file mode 100644
index 0000000000..e53683b0ef
--- /dev/null
+++ b/src/components/views/elements/DesktopCapturerSourcePicker.tsx
@@ -0,0 +1,166 @@
+/*
+Copyright 2021 Šimon Brandner <simon.bra.ag@gmail.com>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import React from 'react';
+import { _t } from '../../../languageHandler';
+import BaseDialog from "..//dialogs/BaseDialog"
+import AccessibleButton from './AccessibleButton';
+import {getDesktopCapturerSources} from "matrix-js-sdk/src/webrtc/call";
+
+export interface DesktopCapturerSource {
+    id: string;
+    name: string;
+    thumbnailURL;
+}
+
+export enum Tabs {
+    Screens = "screens",
+    Windows = "windows",
+}
+
+export interface DesktopCapturerSourceIProps {
+    source: DesktopCapturerSource;
+    onSelect(source: DesktopCapturerSource): void;
+}
+
+export class ExistingSource extends React.Component<DesktopCapturerSourceIProps> {
+    constructor(props) {
+        super(props);
+    }
+
+    onClick = (ev) => {
+        this.props.onSelect(this.props.source);
+    }
+
+    render() {
+        return (
+            <AccessibleButton
+                className="mx_desktopCapturerSourcePicker_stream_button"
+                title={this.props.source.name}
+                onClick={this.onClick} >
+                <img
+                    className="mx_desktopCapturerSourcePicker_stream_thumbnail"
+                    src={this.props.source.thumbnailURL}
+                />
+                <span className="mx_desktopCapturerSourcePicker_stream_name">{this.props.source.name}</span>
+            </AccessibleButton>
+        );
+    }
+}
+
+export interface DesktopCapturerSourcePickerIState {
+    selectedTab: Tabs;
+    sources: Array<DesktopCapturerSource>;
+}
+export interface DesktopCapturerSourcePickerIProps {
+    onFinished(source: DesktopCapturerSource): void;
+}
+
+export default class DesktopCapturerSourcePicker extends React.Component<
+    DesktopCapturerSourcePickerIProps,
+    DesktopCapturerSourcePickerIState
+    > {
+    interval;
+
+    constructor(props) {
+        super(props);
+
+        this.state = {
+            selectedTab: Tabs.Screens,
+            sources: [],
+        };
+    }
+
+    componentDidMount() {
+        // We update the sources every 500ms to get newer thumbnails
+        this.interval = setInterval(async () => {
+            this.setState({
+                sources: await getDesktopCapturerSources(),
+            });
+        }, 500);
+    }
+
+    componentWillUnmount() {
+        clearInterval(this.interval);
+    }
+
+    onSelect = (source) => {
+        this.props.onFinished(source);
+    }
+
+    onScreensClick = (ev) => {
+        this.setState({selectedTab: Tabs.Screens});
+    }
+
+    onWindowsClick = (ev) => {
+        this.setState({selectedTab: Tabs.Windows});
+    }
+
+    onCloseClick = (ev) => {
+        this.props.onFinished(null);
+    }
+
+    render() {
+        let sources;
+        if (this.state.selectedTab === Tabs.Screens) {
+            sources = this.state.sources
+                .filter((source) => {
+                    return source.id.startsWith("screen");
+                })
+                .map((source) => {
+                    return <ExistingSource source={source} onSelect={this.onSelect} key={source.id} />;
+                });
+        } else {
+            sources = this.state.sources
+                .filter((source) => {
+                    return source.id.startsWith("window");
+                })
+                .map((source) => {
+                    return <ExistingSource source={source} onSelect={this.onSelect} key={source.id} />;
+                });
+        }
+
+        const buttonStyle = "mx_desktopCapturerSourcePicker_tabLabel";
+        const screensButtonStyle = buttonStyle + ((this.state.selectedTab === Tabs.Screens) ? "_selected" : "");
+        const windowsButtonStyle = buttonStyle + ((this.state.selectedTab === Tabs.Windows) ? "_selected" : "");
+
+        return (
+            <BaseDialog
+                className="mx_desktopCapturerSourcePicker"
+                onFinished={this.onCloseClick}
+                title={_t("Share your screen")}
+            >
+                <div className="mx_desktopCapturerSourcePicker_tabLabels">
+                    <AccessibleButton
+                        className={screensButtonStyle}
+                        onClick={this.onScreensClick}
+                    >
+                        {_t("Screens")}
+                    </AccessibleButton>
+                    <AccessibleButton
+                        className={windowsButtonStyle}
+                        onClick={this.onWindowsClick}
+                    >
+                        {_t("Windows")}
+                    </AccessibleButton>
+                </div>
+                <div className="mx_desktopCapturerSourcePicker_panel">
+                    { sources }
+                </div>
+            </BaseDialog>
+        );
+    }
+}
diff --git a/src/components/views/messages/TextualBody.js b/src/components/views/messages/TextualBody.js
index bf0884a2f3..71f7572a25 100644
--- a/src/components/views/messages/TextualBody.js
+++ b/src/components/views/messages/TextualBody.js
@@ -81,6 +81,7 @@ export default class TextualBody extends React.Component {
     }
 
     _applyFormatting() {
+        const showLineNumbers = SettingsStore.getValue("showCodeLineNumbers");
         this.activateSpoilers([this._content.current]);
 
         // pillifyLinks BEFORE linkifyElement because plain room/user URLs in the composer
@@ -91,29 +92,136 @@ export default class TextualBody extends React.Component {
         this.calculateUrlPreview();
 
         if (this.props.mxEvent.getContent().format === "org.matrix.custom.html") {
-            const blocks = ReactDOM.findDOMNode(this).getElementsByTagName("code");
-            if (blocks.length > 0) {
-                // Do this asynchronously: parsing code takes time and we don't
-                // need to block the DOM update on it.
-                setTimeout(() => {
-                    if (this._unmounted) return;
-                    for (let i = 0; i < blocks.length; i++) {
-                        if (SettingsStore.getValue("enableSyntaxHighlightLanguageDetection")) {
-                            highlight.highlightBlock(blocks[i]);
-                        } else {
-                            // Only syntax highlight if there's a class starting with language-
-                            const classes = blocks[i].className.split(/\s+/).filter(function(cl) {
-                                return cl.startsWith('language-') && !cl.startsWith('language-_');
-                            });
-
-                            if (classes.length != 0) {
-                                highlight.highlightBlock(blocks[i]);
-                            }
-                        }
+            // Handle expansion and add buttons
+            const pres = ReactDOM.findDOMNode(this).getElementsByTagName("pre");
+            if (pres.length > 0) {
+                for (let i = 0; i < pres.length; i++) {
+                    // Wrap a div around <pre> so that the copy button can be correctly positioned
+                    // when the <pre> overflows and is scrolled horizontally.
+                    const div = this._wrapInDiv(pres[i]);
+                    this._handleCodeBlockExpansion(pres[i]);
+                    this._addCodeExpansionButton(div, pres[i]);
+                    this._addCodeCopyButton(div);
+                    if (showLineNumbers) {
+                        this._addLineNumbers(pres[i]);
                     }
-                }, 10);
+                }
+            }
+            // Highlight code
+            const codes = ReactDOM.findDOMNode(this).getElementsByTagName("code");
+            if (codes.length > 0) {
+                for (let i = 0; i < codes.length; i++) {
+                    // Do this asynchronously: parsing code takes time and we don't
+                    // need to block the DOM update on it.
+                    setTimeout(() => {
+                        if (this._unmounted) return;
+                        for (let i = 0; i < pres.length; i++) {
+                            this._highlightCode(codes[i]);
+                        }
+                    }, 10);
+                }
+            }
+        }
+    }
+
+    _addCodeExpansionButton(div, pre) {
+        // Calculate how many percent does the pre element take up.
+        // If it's less than 30% we don't add the expansion button.
+        const percentageOfViewport = pre.offsetHeight / window.innerHeight * 100;
+        if (percentageOfViewport < 30) return;
+
+        const button = document.createElement("span");
+        button.className = "mx_EventTile_button ";
+        if (pre.className == "mx_EventTile_collapsedCodeBlock") {
+            button.className += "mx_EventTile_expandButton";
+        } else {
+            button.className += "mx_EventTile_collapseButton";
+        }
+
+        button.onclick = async () => {
+            button.className = "mx_EventTile_button ";
+            if (pre.className == "mx_EventTile_collapsedCodeBlock") {
+                pre.className = "";
+                button.className += "mx_EventTile_collapseButton";
+            } else {
+                pre.className = "mx_EventTile_collapsedCodeBlock";
+                button.className += "mx_EventTile_expandButton";
+            }
+
+            // By expanding/collapsing we changed
+            // the height, therefore we call this
+            this.props.onHeightChanged();
+        };
+
+        div.appendChild(button);
+    }
+
+    _addCodeCopyButton(div) {
+        const button = document.createElement("span");
+        button.className = "mx_EventTile_button mx_EventTile_copyButton ";
+
+        // Check if expansion button exists. If so
+        // we put the copy button to the bottom
+        const expansionButtonExists = div.getElementsByClassName("mx_EventTile_button");
+        if (expansionButtonExists.length > 0) button.className += "mx_EventTile_buttonBottom";
+
+        button.onclick = async () => {
+            const copyCode = button.parentNode.getElementsByTagName("code")[0];
+            const successful = await copyPlaintext(copyCode.textContent);
+
+            const buttonRect = button.getBoundingClientRect();
+            const GenericTextContextMenu = sdk.getComponent('context_menus.GenericTextContextMenu');
+            const {close} = ContextMenu.createMenu(GenericTextContextMenu, {
+                ...toRightOf(buttonRect, 2),
+                message: successful ? _t('Copied!') : _t('Failed to copy'),
+            });
+            button.onmouseleave = close;
+        };
+
+        div.appendChild(button);
+    }
+
+    _wrapInDiv(pre) {
+        const div = document.createElement("div");
+        div.className = "mx_EventTile_pre_container";
+
+        // Insert containing div in place of <pre> block
+        pre.parentNode.replaceChild(div, pre);
+        // Append <pre> block and copy button to container
+        div.appendChild(pre);
+
+        return div;
+    }
+
+    _handleCodeBlockExpansion(pre) {
+        if (!SettingsStore.getValue("expandCodeByDefault")) {
+            pre.className = "mx_EventTile_collapsedCodeBlock";
+        }
+    }
+
+    _addLineNumbers(pre) {
+        pre.innerHTML = '<span class="mx_EventTile_lineNumbers"></span>' + pre.innerHTML + '<span></span>';
+        const lineNumbers = pre.getElementsByClassName("mx_EventTile_lineNumbers")[0];
+        // Calculate number of lines in pre
+        const number = pre.innerHTML.split(/\n/).length;
+        // Iterate through lines starting with 1 (number of the first line is 1)
+        for (let i = 1; i < number; i++) {
+            lineNumbers.innerHTML += '<span class="mx_EventTile_lineNumber">' + i + '</span>';
+        }
+    }
+
+    _highlightCode(code) {
+        if (SettingsStore.getValue("enableSyntaxHighlightLanguageDetection")) {
+            highlight.highlightBlock(code);
+        } else {
+            // Only syntax highlight if there's a class starting with language-
+            const classes = code.className.split(/\s+/).filter(function(cl) {
+                return cl.startsWith('language-') && !cl.startsWith('language-_');
+            });
+
+            if (classes.length != 0) {
+                highlight.highlightBlock(code);
             }
-            this._addCodeCopyButton();
         }
     }
 
@@ -254,38 +362,6 @@ export default class TextualBody extends React.Component {
         }
     }
 
-    _addCodeCopyButton() {
-        // Add 'copy' buttons to pre blocks
-        Array.from(ReactDOM.findDOMNode(this).querySelectorAll('.mx_EventTile_body pre')).forEach((p) => {
-            const button = document.createElement("span");
-            button.className = "mx_EventTile_copyButton";
-            button.onclick = async () => {
-                const copyCode = button.parentNode.getElementsByTagName("pre")[0];
-                const successful = await copyPlaintext(copyCode.textContent);
-
-                const buttonRect = button.getBoundingClientRect();
-                const GenericTextContextMenu = sdk.getComponent('context_menus.GenericTextContextMenu');
-                const {close} = ContextMenu.createMenu(GenericTextContextMenu, {
-                    ...toRightOf(buttonRect, 2),
-                    message: successful ? _t('Copied!') : _t('Failed to copy'),
-                });
-                button.onmouseleave = close;
-            };
-
-            // Wrap a div around <pre> so that the copy button can be correctly positioned
-            // when the <pre> overflows and is scrolled horizontally.
-            const div = document.createElement("div");
-            div.className = "mx_EventTile_pre_container";
-
-            // Insert containing div in place of <pre> block
-            p.parentNode.replaceChild(div, p);
-
-            // Append <pre> block and copy button to container
-            div.appendChild(p);
-            div.appendChild(button);
-        });
-    }
-
     onCancelClick = event => {
         this.setState({ widgetHidden: true });
         // FIXME: persist this somewhere smarter than local storage
diff --git a/src/components/views/room_settings/RoomProfileSettings.js b/src/components/views/room_settings/RoomProfileSettings.js
index c76c0823e4..c651216e8c 100644
--- a/src/components/views/room_settings/RoomProfileSettings.js
+++ b/src/components/views/room_settings/RoomProfileSettings.js
@@ -69,19 +69,24 @@ export default class RoomProfileSettings extends React.Component {
         // clear file upload field so same file can be selected
         this._avatarUpload.current.value = "";
         this.setState({
-            avatarUrl: undefined,
-            avatarFile: undefined,
+            avatarUrl: null,
+            avatarFile: null,
             enableProfileSave: true,
         });
     };
 
-    _clearProfile = async (e) => {
+    _cancelProfileChanges = async (e) => {
         e.stopPropagation();
         e.preventDefault();
 
         if (!this.state.enableProfileSave) return;
-        this._removeAvatar();
-        this.setState({enableProfileSave: false, displayName: this.state.originalDisplayName});
+        this.setState({
+            enableProfileSave: false,
+            displayName: this.state.originalDisplayName,
+            topic: this.state.originalTopic,
+            avatarUrl: this.state.originalAvatarUrl,
+            avatarFile: null,
+        });
     };
 
     _saveProfile = async (e) => {
@@ -108,7 +113,7 @@ export default class RoomProfileSettings extends React.Component {
             newState.originalAvatarUrl = newState.avatarUrl;
             newState.avatarFile = null;
         } else if (this.state.originalAvatarUrl !== this.state.avatarUrl) {
-            await client.sendStateEvent(this.props.roomId, 'm.room.avatar', {url: undefined}, '');
+            await client.sendStateEvent(this.props.roomId, 'm.room.avatar', {}, '');
         }
 
         if (this.state.originalTopic !== this.state.topic) {
@@ -164,11 +169,15 @@ export default class RoomProfileSettings extends React.Component {
         const AvatarSetting = sdk.getComponent('settings.AvatarSetting');
 
         let profileSettingsButtons;
-        if (this.state.canSetTopic && this.state.canSetName) {
+        if (
+            this.state.canSetName ||
+            this.state.canSetTopic ||
+            this.state.canSetAvatar
+        ) {
             profileSettingsButtons = (
                 <div className="mx_ProfileSettings_buttons">
                     <AccessibleButton
-                        onClick={this._clearProfile}
+                        onClick={this._cancelProfileChanges}
                         kind="link"
                         disabled={!this.state.enableProfileSave}
                     >
diff --git a/src/components/views/rooms/MessageComposer.js b/src/components/views/rooms/MessageComposer.js
index da430e622a..6a867386f7 100644
--- a/src/components/views/rooms/MessageComposer.js
+++ b/src/components/views/rooms/MessageComposer.js
@@ -426,7 +426,8 @@ export default class MessageComposer extends React.Component {
                 <EmojiButton key="emoji_button" addEmoji={this.addEmoji} />,
             );
 
-            if (SettingsStore.getValue(UIFeature.Widgets)) {
+            if (SettingsStore.getValue(UIFeature.Widgets) &&
+                SettingsStore.getValue("MessageComposerInput.showStickersButton")) {
                 controls.push(<Stickerpicker key="stickerpicker_controls_button" room={this.props.room} />);
             }
 
diff --git a/src/components/views/rooms/RoomBreadcrumbs.tsx b/src/components/views/rooms/RoomBreadcrumbs.tsx
index 7725ce456e..ff60ab7779 100644
--- a/src/components/views/rooms/RoomBreadcrumbs.tsx
+++ b/src/components/views/rooms/RoomBreadcrumbs.tsx
@@ -111,7 +111,7 @@ export default class RoomBreadcrumbs extends React.PureComponent<IProps, IState>
                     appear={true} in={this.state.doAnimation} timeout={640}
                     classNames='mx_RoomBreadcrumbs'
                 >
-                    <Toolbar className='mx_RoomBreadcrumbs'>
+                    <Toolbar className='mx_RoomBreadcrumbs' aria-label={_t("Recently visited rooms")}>
                         {tiles.slice(this.state.skipFirst ? 1 : 0)}
                     </Toolbar>
                 </CSSTransition>
diff --git a/src/components/views/rooms/SendMessageComposer.js b/src/components/views/rooms/SendMessageComposer.js
index 7b516e1f52..62c474e417 100644
--- a/src/components/views/rooms/SendMessageComposer.js
+++ b/src/components/views/rooms/SendMessageComposer.js
@@ -403,6 +403,7 @@ export default class SendMessageComposer extends React.Component {
         this._editorRef.clearUndoHistory();
         this._editorRef.focus();
         this._clearStoredEditorState();
+        dis.dispatch({action: "scroll_to_bottom"});
     }
 
     componentWillUnmount() {
diff --git a/src/components/views/settings/ProfileSettings.js b/src/components/views/settings/ProfileSettings.js
index c11a2e3a5e..4dc69884c3 100644
--- a/src/components/views/settings/ProfileSettings.js
+++ b/src/components/views/settings/ProfileSettings.js
@@ -52,19 +52,23 @@ export default class ProfileSettings extends React.Component {
         // clear file upload field so same file can be selected
         this._avatarUpload.current.value = "";
         this.setState({
-            avatarUrl: undefined,
-            avatarFile: undefined,
+            avatarUrl: null,
+            avatarFile: null,
             enableProfileSave: true,
         });
     };
 
-    _clearProfile = async (e) => {
+    _cancelProfileChanges = async (e) => {
         e.stopPropagation();
         e.preventDefault();
 
         if (!this.state.enableProfileSave) return;
-        this._removeAvatar();
-        this.setState({enableProfileSave: false, displayName: this.state.originalDisplayName});
+        this.setState({
+            enableProfileSave: false,
+            displayName: this.state.originalDisplayName,
+            avatarUrl: this.state.originalAvatarUrl,
+            avatarFile: null,
+        });
     };
 
     _saveProfile = async (e) => {
@@ -186,7 +190,7 @@ export default class ProfileSettings extends React.Component {
                 </div>
                 <div className="mx_ProfileSettings_buttons">
                     <AccessibleButton
-                        onClick={this._clearProfile}
+                        onClick={this._cancelProfileChanges}
                         kind="link"
                         disabled={!this.state.enableProfileSave}
                     >
diff --git a/src/components/views/settings/tabs/user/PreferencesUserSettingsTab.js b/src/components/views/settings/tabs/user/PreferencesUserSettingsTab.js
index a32549b326..04fcea39dc 100644
--- a/src/components/views/settings/tabs/user/PreferencesUserSettingsTab.js
+++ b/src/components/views/settings/tabs/user/PreferencesUserSettingsTab.js
@@ -34,6 +34,7 @@ export default class PreferencesUserSettingsTab extends React.Component {
         'MessageComposerInput.suggestEmoji',
         'sendTypingNotifications',
         'MessageComposerInput.ctrlEnterToSend',
+        'MessageComposerInput.showStickersButton',
     ];
 
     static TIMELINE_SETTINGS = [
@@ -46,6 +47,8 @@ export default class PreferencesUserSettingsTab extends React.Component {
         'alwaysShowTimestamps',
         'showRedactions',
         'enableSyntaxHighlightLanguageDetection',
+        'expandCodeByDefault',
+        'showCodeLineNumbers',
         'showJoinLeaves',
         'showAvatarChanges',
         'showDisplaynameChanges',
diff --git a/src/i18n/strings/en_EN.json b/src/i18n/strings/en_EN.json
index 347f12f9fa..9a01af7d40 100644
--- a/src/i18n/strings/en_EN.json
+++ b/src/i18n/strings/en_EN.json
@@ -795,6 +795,7 @@
     "Font size": "Font size",
     "Use custom size": "Use custom size",
     "Enable Emoji suggestions while typing": "Enable Emoji suggestions while typing",
+    "Show stickers button": "Show stickers button",
     "Use a more compact ‘Modern’ layout": "Use a more compact ‘Modern’ layout",
     "Show a placeholder for removed messages": "Show a placeholder for removed messages",
     "Show join/leave messages (invites/kicks/bans unaffected)": "Show join/leave messages (invites/kicks/bans unaffected)",
@@ -805,6 +806,8 @@
     "Always show message timestamps": "Always show message timestamps",
     "Autoplay GIFs and videos": "Autoplay GIFs and videos",
     "Enable automatic language detection for syntax highlighting": "Enable automatic language detection for syntax highlighting",
+    "Expand code blocks by default": "Expand code blocks by default",
+    "Show line numbers in code blocks": "Show line numbers in code blocks",
     "Show avatars in user and room mentions": "Show avatars in user and room mentions",
     "Enable big emoji in chat": "Enable big emoji in chat",
     "Send typing notifications": "Send typing notifications",
@@ -1462,6 +1465,7 @@
     "Seen by %(displayName)s (%(userName)s) at %(dateTime)s": "Seen by %(displayName)s (%(userName)s) at %(dateTime)s",
     "Replying": "Replying",
     "Room %(name)s": "Room %(name)s",
+    "Recently visited rooms": "Recently visited rooms",
     "No recently visited rooms": "No recently visited rooms",
     "No rooms to show": "No rooms to show",
     "Unnamed room": "Unnamed room",
@@ -1851,6 +1855,9 @@
     "Use the <a>Desktop app</a> to search encrypted messages": "Use the <a>Desktop app</a> to search encrypted messages",
     "This version of %(brand)s does not support viewing some encrypted files": "This version of %(brand)s does not support viewing some encrypted files",
     "This version of %(brand)s does not support searching encrypted messages": "This version of %(brand)s does not support searching encrypted messages",
+    "Share your screen": "Share your screen",
+    "Screens": "Screens",
+    "Windows": "Windows",
     "Join": "Join",
     "No results": "No results",
     "Please <newIssueLink>create a new issue</newIssueLink> on GitHub so that we can investigate this bug.": "Please <newIssueLink>create a new issue</newIssueLink> on GitHub so that we can investigate this bug.",
diff --git a/src/settings/Settings.ts b/src/settings/Settings.ts
index 6415723f56..385b892478 100644
--- a/src/settings/Settings.ts
+++ b/src/settings/Settings.ts
@@ -240,6 +240,11 @@ export const SETTINGS: {[setting: string]: ISetting} = {
         default: true,
         invertedSettingName: 'MessageComposerInput.dontSuggestEmoji',
     },
+    "MessageComposerInput.showStickersButton": {
+        supportedLevels: LEVELS_ACCOUNT_SETTINGS,
+        displayName: _td('Show stickers button'),
+        default: true,
+    },
     // TODO: Wire up appropriately to UI (FTUE notifications)
     "Notifications.alwaysShowBadgeCounts": {
         supportedLevels: LEVELS_ROOM_OR_ACCOUNT,
@@ -300,6 +305,16 @@ export const SETTINGS: {[setting: string]: ISetting} = {
         displayName: _td('Enable automatic language detection for syntax highlighting'),
         default: false,
     },
+    "expandCodeByDefault": {
+        supportedLevels: LEVELS_ACCOUNT_SETTINGS,
+        displayName: _td('Expand code blocks by default'),
+        default: false,
+    },
+    "showCodeLineNumbers": {
+        supportedLevels: LEVELS_ACCOUNT_SETTINGS,
+        displayName: _td('Show line numbers in code blocks'),
+        default: true,
+    },
     "Pill.shouldShowPillAvatar": {
         supportedLevels: LEVELS_ACCOUNT_SETTINGS,
         displayName: _td('Show avatars in user and room mentions'),