diff --git a/desktop/app/src/PluginContainer.tsx b/desktop/app/src/PluginContainer.tsx
index 288cd17db..a43efbb6b 100644
--- a/desktop/app/src/PluginContainer.tsx
+++ b/desktop/app/src/PluginContainer.tsx
@@ -45,7 +45,7 @@ import {activateMenuItems} from './MenuBar';
 import {Message} from './reducers/pluginMessageQueue';
 import {Idler} from './utils/Idler';
 import {processMessageQueue} from './utils/messageQueue';
-import {ToggleButton, SmallText} from './ui';
+import {ToggleButton, SmallText, Layout} from './ui';
 import {SandyPluginRenderer} from 'flipper-plugin';
 import {isDevicePluginDefinition} from './utils/pluginUtils';
 import ArchivedDevice from './devices/ArchivedDevice';
@@ -67,7 +67,6 @@ const Waiting = styled(FlexColumn)({
   width: '100%',
   height: '100%',
   flexGrow: 1,
-  background: colors.light02,
   alignItems: 'center',
   justifyContent: 'center',
   textAlign: 'center',
@@ -95,6 +94,7 @@ const ProgressBarBar = styled.div<{progress: number}>(({progress}) => ({
 
 type OwnProps = {
   logger: Logger;
+  isSandy?: boolean;
 };
 
 type StateFromProps = {
@@ -362,6 +362,7 @@ class PluginContainer extends PureComponent<Props, State> {
       isArchivedDevice,
       selectedApp,
       settingsState,
+      isSandy,
     } = this.props;
     if (!activePlugin || !target || !pluginKey) {
       console.warn(`No selected plugin. Rendering empty!`);
@@ -429,7 +430,17 @@ class PluginContainer extends PureComponent<Props, State> {
       };
       pluginElement = React.createElement(activePlugin, props);
     }
-    return (
+    return isSandy ? (
+      <Layout.Right>
+        <ErrorBoundary
+          heading={`Plugin "${
+            activePlugin.title || 'Unknown'
+          }" encountered an error during render`}>
+          {pluginElement}
+        </ErrorBoundary>
+        <SidebarContainer id="detailsSidebar" />
+      </Layout.Right>
+    ) : (
       <React.Fragment>
         <Container key="plugin">
           <ErrorBoundary
diff --git a/desktop/app/src/chrome/DetailSidebar.tsx b/desktop/app/src/chrome/DetailSidebar.tsx
index 1924fff6d..83701c30e 100644
--- a/desktop/app/src/chrome/DetailSidebar.tsx
+++ b/desktop/app/src/chrome/DetailSidebar.tsx
@@ -7,12 +7,14 @@
  * @format
  */
 
-import React from 'react';
+import React, {useEffect, useMemo, useContext} from 'react';
 import ReactDOM from 'react-dom';
+import {ReactReduxContext} from 'react-redux';
 import Sidebar from '../ui/components/Sidebar';
-import {connect} from 'react-redux';
 import {toggleRightSidebarAvailable} from '../reducers/application';
-import {State as Store} from '../reducers';
+import {useDispatch, useStore} from '../utils/useStore';
+import {useIsSandy} from '../sandy-chrome/SandyContext';
+import {ContentContainer} from '../sandy-chrome/ContentContainer';
 
 type OwnProps = {
   children: any;
@@ -20,57 +22,47 @@ type OwnProps = {
   minWidth?: number;
 };
 
-type StateFromProps = {
-  rightSidebarVisible: boolean;
-  rightSidebarAvailable: boolean;
-};
+/* eslint-disable react-hooks/rules-of-hooks */
+export default function DetailSidebar({children, width, minWidth}: OwnProps) {
+  const reduxContext = useContext(ReactReduxContext);
+  const domNode = useMemo(() => document.getElementById('detailsSidebar'), []);
 
-type DispatchFromProps = {
-  toggleRightSidebarAvailable: (visible?: boolean) => any;
-};
-
-type Props = OwnProps & StateFromProps & DispatchFromProps;
-class DetailSidebar extends React.Component<Props> {
-  componentDidMount() {
-    this.updateSidebarAvailablility();
+  if (!reduxContext || !domNode) {
+    // For unit tests, make sure to render elements inline
+    return <div id="detailsSidebar">{children}</div>;
   }
 
-  componentDidUpdate() {
-    this.updateSidebarAvailablility();
-  }
+  const isSandy = useIsSandy();
+  const dispatch = useDispatch();
+  const {rightSidebarAvailable, rightSidebarVisible} = useStore((state) => {
+    const {rightSidebarAvailable, rightSidebarVisible} = state.application;
+    return {rightSidebarAvailable, rightSidebarVisible};
+  });
 
-  updateSidebarAvailablility() {
-    const available = Boolean(this.props.children);
-    if (available !== this.props.rightSidebarAvailable) {
-      this.props.toggleRightSidebarAvailable(available);
-    }
-  }
+  useEffect(
+    function updateSidebarAvailablility() {
+      const available = Boolean(children);
+      if (available !== rightSidebarAvailable) {
+        dispatch(toggleRightSidebarAvailable(available));
+      }
+    },
+    [children, rightSidebarAvailable, dispatch],
+  );
 
-  render() {
-    const domNode = document.getElementById('detailsSidebar');
-    return (
-      this.props.children &&
-      this.props.rightSidebarVisible &&
+  return (
+    (children &&
+      rightSidebarVisible &&
       domNode &&
       ReactDOM.createPortal(
         <Sidebar
-          minWidth={this.props.minWidth}
-          width={this.props.width || 300}
-          position="right">
-          {this.props.children}
+          minWidth={minWidth}
+          width={width || 300}
+          position="right"
+          gutter={isSandy}>
+          {isSandy ? <ContentContainer>{children}</ContentContainer> : children}
         </Sidebar>,
         domNode,
-      )
-    );
-  }
+      )) ||
+    null
+  );
 }
-
-export default connect<StateFromProps, DispatchFromProps, OwnProps, Store>(
-  ({application: {rightSidebarVisible, rightSidebarAvailable}}) => ({
-    rightSidebarVisible,
-    rightSidebarAvailable,
-  }),
-  {
-    toggleRightSidebarAvailable,
-  },
-)(DetailSidebar);
diff --git a/desktop/app/src/chrome/mainsidebar/MainSidebarUtilsSection.tsx b/desktop/app/src/chrome/mainsidebar/MainSidebarUtilsSection.tsx
index 5c5ac8314..6543f739f 100644
--- a/desktop/app/src/chrome/mainsidebar/MainSidebarUtilsSection.tsx
+++ b/desktop/app/src/chrome/mainsidebar/MainSidebarUtilsSection.tsx
@@ -19,7 +19,6 @@ import {StaticView, setStaticView} from '../../reducers/connections';
 import {setActiveSheet} from '../../reducers/application';
 import UserAccount from '../UserAccount';
 import SupportRequestFormV2 from '../../fb-stubs/SupportRequestFormV2';
-import WatchTools from '../../fb-stubs/WatchTools';
 import {
   isStaticViewActive,
   PluginIcon,
@@ -32,6 +31,7 @@ import {ConsoleLogs, errorCounterAtom} from '../ConsoleLogs';
 import {useValue} from 'flipper-plugin';
 import {colors} from '../../ui';
 import GK from '../../fb-stubs/GK';
+import WatchTools from '../../fb-stubs/WatchTools';
 
 type OwnProps = {};
 
diff --git a/desktop/app/src/sandy-chrome/ContentContainer.tsx b/desktop/app/src/sandy-chrome/ContentContainer.tsx
new file mode 100644
index 000000000..bddaaabea
--- /dev/null
+++ b/desktop/app/src/sandy-chrome/ContentContainer.tsx
@@ -0,0 +1,19 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+import {Layout, styled} from '../ui';
+import {theme} from './theme';
+
+export const ContentContainer = styled(Layout.Container)({
+  overflow: 'hidden',
+  background: theme.backgroundDefault,
+  border: `1px solid ${theme.dividerColor}`,
+  borderRadius: theme.containerBorderRadius,
+  boxShadow: `0px 0px 5px rgba(0, 0, 0, 0.05), 0px 0px 1px rgba(0, 0, 0, 0.05)`,
+});
diff --git a/desktop/app/src/sandy-chrome/LeftRail.tsx b/desktop/app/src/sandy-chrome/LeftRail.tsx
index 60f430cc2..9d2291c97 100644
--- a/desktop/app/src/sandy-chrome/LeftRail.tsx
+++ b/desktop/app/src/sandy-chrome/LeftRail.tsx
@@ -8,7 +8,6 @@
  */
 
 import React, {cloneElement, useState, useCallback, useMemo} from 'react';
-import {styled, Layout} from '../ui';
 import {Button, Divider, Badge, Tooltip, Avatar, Popover} from 'antd';
 import {
   MobileFilled,
@@ -23,7 +22,10 @@ import {
 } from '@ant-design/icons';
 import {SidebarLeft, SidebarRight} from './SandyIcons';
 import {useDispatch, useStore} from '../utils/useStore';
-import {toggleLeftSidebarVisible} from '../reducers/application';
+import {
+  toggleLeftSidebarVisible,
+  toggleRightSidebarVisible,
+} from '../reducers/application';
 import {theme} from './theme';
 import SetupDoctorScreen, {checkHasNewProblem} from './SetupDoctorScreen';
 import SettingsSheet from '../chrome/SettingsSheet';
@@ -34,6 +36,8 @@ import {ToplevelProps} from './SandyApp';
 import {useValue} from 'flipper-plugin';
 import {logout} from '../reducers/user';
 import config from '../fb-stubs/config';
+import Layout from '../ui/components/Layout';
+import styled from '@emotion/styled';
 
 const LeftRailButtonElem = styled(Button)<{kind?: 'small'}>(({kind}) => ({
   width: kind === 'small' ? 32 : 36,
@@ -52,11 +56,13 @@ function LeftRailButton({
   count,
   title,
   onClick,
+  disabled,
 }: {
   icon?: React.ReactElement;
   small?: boolean;
   toggled?: boolean;
-  selected?: boolean; // TODO: make sure only one element can be selected
+  selected?: boolean;
+  disabled?: boolean;
   count?: number | true;
   title: string;
   onClick?: React.MouseEventHandler<HTMLElement>;
@@ -78,6 +84,7 @@ function LeftRailButton({
         type={selected ? 'primary' : 'ghost'}
         icon={iconElement}
         onClick={onClick}
+        disabled={disabled}
         style={{
           color: toggled ? theme.primaryColor : undefined,
           background: toggled ? theme.backgroundWash : undefined,
@@ -99,9 +106,9 @@ export function LeftRail({
   setToplevelSelection,
 }: ToplevelProps) {
   return (
-    <Layout.Container borderRight padv={12} padh={6} width={48}>
+    <Layout.Container borderRight padv={12} width={48}>
       <Layout.Bottom>
-        <Layout.Vertical center gap={10}>
+        <Layout.Vertical center gap={10} padh={6}>
           <LeftRailButton
             icon={<MobileFilled />}
             title="App Inspect"
@@ -118,7 +125,7 @@ export function LeftRail({
             setToplevelSelection={setToplevelSelection}
           />
         </Layout.Vertical>
-        <Layout.Vertical center gap={10}>
+        <Layout.Vertical center gap={10} padh={6}>
           <SetupDoctorButton />
           <WelcomeScreenButton />
           <ShowSettingsButton />
@@ -127,11 +134,7 @@ export function LeftRail({
             small
             title="Feedback / Bug Reporter"
           />
-          <LeftRailButton
-            icon={<SidebarRight />}
-            small
-            title="Right Sidebar Toggle"
-          />
+          <RightSidebarToggleButton />
           <LeftSidebarToggleButton />
           {config.showLogin && <LoginButton />}
         </Layout.Vertical>
@@ -141,12 +144,11 @@ export function LeftRail({
 }
 
 function LeftSidebarToggleButton() {
+  const dispatch = useDispatch();
   const mainMenuVisible = useStore(
     (state) => state.application.leftSidebarVisible,
   );
 
-  const dispatch = useDispatch();
-
   return (
     <LeftRailButton
       icon={<SidebarLeft />}
@@ -160,6 +162,29 @@ function LeftSidebarToggleButton() {
   );
 }
 
+function RightSidebarToggleButton() {
+  const dispatch = useDispatch();
+  const rightSidebarAvailable = useStore(
+    (state) => state.application.rightSidebarAvailable,
+  );
+  const rightSidebarVisible = useStore(
+    (state) => state.application.rightSidebarVisible,
+  );
+
+  return (
+    <LeftRailButton
+      icon={<SidebarRight />}
+      small
+      title="Right Sidebar Toggle"
+      toggled={rightSidebarVisible}
+      disabled={!rightSidebarAvailable}
+      onClick={() => {
+        dispatch(toggleRightSidebarVisible());
+      }}
+    />
+  );
+}
+
 function DebugLogsButton({
   toplevelSelection,
   setToplevelSelection,
diff --git a/desktop/app/src/sandy-chrome/SandyApp.tsx b/desktop/app/src/sandy-chrome/SandyApp.tsx
index 5dfe97a81..accc8731b 100644
--- a/desktop/app/src/sandy-chrome/SandyApp.tsx
+++ b/desktop/app/src/sandy-chrome/SandyApp.tsx
@@ -23,6 +23,7 @@ import {setStaticView} from '../reducers/connections';
 import {toggleLeftSidebarVisible} from '../reducers/application';
 import {AppInspect} from './appinspect/AppInspect';
 import PluginContainer from '../PluginContainer';
+import {ContentContainer} from './ContentContainer';
 
 export type ToplevelNavItem = 'appinspect' | 'flipperlogs' | undefined;
 export type ToplevelProps = {
@@ -95,25 +96,15 @@ export function SandyApp({logger}: {logger: Logger}) {
             </Sidebar>
           </Layout.Horizontal>
           <MainContainer>
-            <ContentContainer>
-              {staticView ? (
-                React.createElement(staticView, {
+            {staticView ? (
+              <ContentContainer>
+                {React.createElement(staticView, {
                   logger: logger,
-                })
-              ) : (
-                <PluginContainer logger={logger} />
-              )}
-            </ContentContainer>
-            <Sidebar
-              width={300}
-              minWidth={220}
-              maxWidth={800}
-              gutter
-              position="right">
-              <ContentContainer style={{marginRight: theme.space.large}}>
-                <RightMenu />
+                })}
               </ContentContainer>
-            </Sidebar>
+            ) : (
+              <PluginContainer logger={logger} isSandy />
+            )}
           </MainContainer>
         </Layout.Left>
       </Layout.Top>
@@ -121,19 +112,7 @@ export function SandyApp({logger}: {logger: Logger}) {
   );
 }
 
-const MainContainer = styled(Layout.Right)({
+const MainContainer = styled(Layout.Container)({
   background: theme.backgroundWash,
+  padding: `${theme.space.large}px ${theme.space.large}px ${theme.space.large}px 0`,
 });
-
-export const ContentContainer = styled(Layout.Container)({
-  background: theme.backgroundDefault,
-  border: `1px solid ${theme.dividerColor}`,
-  borderRadius: theme.containerBorderRadius,
-  boxShadow: `0px 0px 5px rgba(0, 0, 0, 0.05), 0px 0px 1px rgba(0, 0, 0, 0.05)`,
-  marginTop: theme.space.large,
-  marginBottom: theme.space.large,
-});
-
-function RightMenu() {
-  return <div>RightMenu</div>;
-}
diff --git a/desktop/app/src/ui/components/Layout.tsx b/desktop/app/src/ui/components/Layout.tsx
index 35fe4392c..bb2a969b1 100644
--- a/desktop/app/src/ui/components/Layout.tsx
+++ b/desktop/app/src/ui/components/Layout.tsx
@@ -45,6 +45,7 @@ const Container = styled.div<ContainerProps>(
     height,
     ...rest
   }) => ({
+    boxSizing: 'border-box',
     minWidth: `0`, // ensures the Container can shrink smaller than it's largest
     width,
     height,
@@ -64,6 +65,7 @@ const Container = styled.div<ContainerProps>(
 );
 
 const ScrollParent = styled.div({
+  boxSizing: 'border-box',
   flex: 1,
   position: 'relative',
   overflow: 'auto',
@@ -141,11 +143,7 @@ const Layout = {
     let [child1, child2] = props.children;
     if (props.scrollable) child2 = <ScrollContainer>{child2}</ScrollContainer>;
     return (
-      <SandySplitContainer
-        {...props}
-        flexDirection="column"
-        flex1={0}
-        flex2={1}>
+      <SandySplitContainer {...props} flexDirection="column" grow={2}>
         {child1}
         {child2}
       </SandySplitContainer>
@@ -157,11 +155,7 @@ const Layout = {
     let [child1, child2] = props.children;
     if (props.scrollable) child1 = <ScrollContainer>{child1}</ScrollContainer>;
     return (
-      <SandySplitContainer
-        {...props}
-        flexDirection="column"
-        flex1={1}
-        flex2={0}>
+      <SandySplitContainer {...props} flexDirection="column" grow={1}>
         {child1}
         {child2}
       </SandySplitContainer>
@@ -173,7 +167,7 @@ const Layout = {
     let [child1, child2] = props.children;
     if (props.scrollable) child2 = <ScrollContainer>{child2}</ScrollContainer>;
     return (
-      <SandySplitContainer {...props} flexDirection="row" flex1={0} flex2={1}>
+      <SandySplitContainer {...props} flexDirection="row" grow={2}>
         {child1}
         {child2}
       </SandySplitContainer>
@@ -185,7 +179,7 @@ const Layout = {
     let [child1, child2] = props.children;
     if (props.scrollable) child1 = <ScrollContainer>{child1}</ScrollContainer>;
     return (
-      <SandySplitContainer {...props} flexDirection="row" flex1={1} flex2={0}>
+      <SandySplitContainer {...props} flexDirection="row" grow={1}>
         {child1}
         {child2}
       </SandySplitContainer>
@@ -202,23 +196,25 @@ Object.keys(Layout).forEach((key) => {
 });
 
 const SandySplitContainer = styled.div<{
-  flex1: number;
-  flex2: number;
+  grow: 1 | 2;
   center?: boolean;
   flexDirection: CSSProperties['flexDirection'];
 }>((props) => ({
+  boxSizing: 'border-box',
   display: 'flex',
   flex: 1,
   flexDirection: props.flexDirection,
   alignItems: props.center ? 'center' : 'stretch',
+  overflow: 'hidden',
   '> :first-child': {
-    flexGrow: props.flex1,
-    flexShrink: props.flex1,
+    flex: props.grow === 1 ? growStyle : fixedStyle,
   },
   '> :last-child': {
-    flexGrow: props.flex2,
-    flexShrink: props.flex2,
+    flex: props.grow === 2 ? growStyle : fixedStyle,
   },
 }));
 
+const fixedStyle = `0 0 auto`;
+const growStyle = `1 0 0`;
+
 export default Layout;
diff --git a/desktop/plugins/seamammals/src/__tests__/seamammals.spec.tsx b/desktop/plugins/seamammals/src/__tests__/seamammals.spec.tsx
index 9b35a2e84..7979c18d1 100644
--- a/desktop/plugins/seamammals/src/__tests__/seamammals.spec.tsx
+++ b/desktop/plugins/seamammals/src/__tests__/seamammals.spec.tsx
@@ -7,20 +7,12 @@
  * @format
  */
 
-import * as React from 'react';
-import * as Flipper from 'flipper';
 // eslint-disable-next-line
 import {act} from '@testing-library/react';
 
 {
   // These mocks are needed because seammammals still uses Flipper in its UI implementation,
   // so we need to mock some things
-
-  // @ts-ignore
-  jest.spyOn(Flipper.DetailSidebar, 'type').mockImplementation((props) => {
-    return <div className="DetailsSidebar">{props.children}</div>;
-  });
-
   const origRequestIdleCallback = window.requestIdleCallback;
   const origCancelIdleCallback = window.cancelIdleCallback;
   // @ts-ignore