diff --git a/src/app/App.tsx b/src/app/App.tsx
index e37b527b..4b21157d 100644
--- a/src/app/App.tsx
+++ b/src/app/App.tsx
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-// Copyright (c) 2020 The Pybricks Authors
+// Copyright (c) 2020-2021 The Pybricks Authors
 
 import { Classes } from '@blueprintjs/core';
 import React, { useState } from 'react';
@@ -17,10 +17,113 @@ import { isMacOS } from '../utils/os';
 import 'react-splitter-layout/lib/index.css';
 import './app.scss';
 
+const Docs: React.FunctionComponent = (_props) => {
+    const dispatch = useDispatch();
+
+    return (
+        <iframe
+            // REVISIT: some of this could be moved to the docs repo
+            // so that it runs earlier to prevent flashing in the UI.
+            // The load event doesn't run until after the page is fully
+            // loaded and there doesn't seem to be a reasonable way to
+            // hook into the iframe to know when it has a new document.
+            onLoad={(e) => {
+                // HACK: this mess restores the scroll position when
+                // the documentation iframe visibility is toggled.
+                // The iframe will be automatically scrolled to 0 when
+                // CSS `display: none` is set.
+
+                const target = e.target as HTMLIFrameElement;
+                const contentWindow = target.contentWindow;
+                if (!contentWindow) {
+                    console.error('could not get iframe content window');
+                    return;
+                }
+
+                // the last "good" scrollY value of the iframe
+                let iframeScroll = 0;
+
+                // This bit monitors the visibility.
+                // https://stackoverflow.com/a/44670818/1976323
+                const observer = new IntersectionObserver(
+                    (entries) => {
+                        entries.forEach((entry) => {
+                            // Restore the scroll position when the iframe is
+                            // shown. Toggling the visibility prevents flashing
+                            // the contents from the top of the page before the
+                            // scroll is done.
+                            if (entry.intersectionRatio > 0) {
+                                contentWindow.scrollTo(0, iframeScroll);
+                                contentWindow.document.documentElement.style.visibility =
+                                    'visible';
+                            } else {
+                                contentWindow.document.documentElement.style.visibility =
+                                    'hidden';
+                            }
+                        });
+                    },
+                    {
+                        root: target.parentElement,
+                    },
+                );
+
+                observer.observe(target);
+
+                // Have to remove he observer, otherwise we end up with
+                // conflicting values when a new page is loaded in the iframe.
+                contentWindow.addEventListener('unload', () => {
+                    observer.unobserve(target);
+                });
+
+                // And this keeps track of the scroll position.
+                contentWindow.addEventListener('scroll', () => {
+                    if (contentWindow.scrollY !== 0) {
+                        // Record the current scroll position. If it is 0, it
+                        // could be that the iframe has been hidden or the user
+                        // scrolled there. So we have to ignore 0. But we don't
+                        // want to be one pixel off if the user really did
+                        // scroll there, so we assume that if the last scroll
+                        // is 1, then the user probably went all the way to 0.
+                        if (contentWindow.scrollY === 1) {
+                            iframeScroll = 0;
+                        } else {
+                            iframeScroll = contentWindow.scrollY;
+                        }
+                    }
+                });
+
+                // Override browser default key bindings in iframe.
+                contentWindow.document.addEventListener('keydown', (e) => {
+                    // use Ctrl-D/Cmd-D to toggle docs
+                    if (
+                        (isMacOS()
+                            ? e.metaKey && !e.ctrlKey
+                            : e.ctrlKey && !e.metaKey) &&
+                        !e.altKey &&
+                        e.key == 'd'
+                    ) {
+                        e.preventDefault();
+                        dispatch(toggleBoolean(BooleanSettingId.ShowDocs));
+                    }
+                });
+
+                if (document.body.classList.contains(Classes.DARK)) {
+                    contentWindow.document.documentElement.classList.add(Classes.DARK);
+                }
+            }}
+            src="static/docs/index.html"
+            allowFullScreen={true}
+            title="docs"
+            width="100%"
+            height="100%"
+            frameBorder="none"
+        />
+    );
+};
+
 const App: React.FunctionComponent = (_props) => {
     const showDocs = useSelector((s: RootState): boolean => s.settings.showDocs);
-    const [dragging, setDragging] = useState(false);
-    const dispatch = useDispatch();
+    const [isDragging, setIsDragging] = useState(false);
 
     return (
         <div className="pb-app">
@@ -29,8 +132,8 @@ const App: React.FunctionComponent = (_props) => {
                 customClassName={`pb-app-body ${
                     showDocs ? 'pb-show-docs' : 'pb-hide-docs'
                 }`}
-                onDragStart={(): void => setDragging(true)}
-                onDragEnd={(): void => setDragging(false)}
+                onDragStart={(): void => setIsDragging(true)}
+                onDragEnd={(): void => setIsDragging(false)}
                 percentage={true}
                 secondaryInitialSize={Number(
                     localStorage.getItem('app-docs-split') || 30,
@@ -55,110 +158,8 @@ const App: React.FunctionComponent = (_props) => {
                     </div>
                 </SplitterLayout>
                 <div className="h-100 w-100">
-                    {dragging && <div className="h-100 w-100 p-absolute" />}
-                    <iframe
-                        // REVISIT: some of this could be moved to the docs repo
-                        // so that it runs earlier to prevent flashing in the UI.
-                        // The load event doesn't run until after the page is fully
-                        // loaded and there doesn't seem to be a reasonable way to
-                        // hook into the iframe to know when it has a new document.
-                        onLoad={(e) => {
-                            // HACK: this mess restores the scroll position when
-                            // the documentation iframe visibility is toggled.
-                            // The iframe will be automatically scrolled to 0 when
-                            // CSS `display: none` is set.
-
-                            const target = e.target as HTMLIFrameElement;
-                            const contentWindow = target.contentWindow;
-                            if (!contentWindow) {
-                                console.error('could not get iframe content window');
-                                return;
-                            }
-
-                            // the last "good" scrollY value of the iframe
-                            let iframeScroll = 0;
-
-                            // This bit monitors the visibility.
-                            // https://stackoverflow.com/a/44670818/1976323
-                            const observer = new IntersectionObserver(
-                                (entries) => {
-                                    entries.forEach((entry) => {
-                                        // Restore the scroll position when the
-                                        // iframe is shown. Toggling the visibility
-                                        // prevents flashing the contents from the
-                                        // top of the page before the scroll is
-                                        // done.
-                                        if (entry.intersectionRatio > 0) {
-                                            contentWindow.scrollTo(0, iframeScroll);
-                                            contentWindow.document.documentElement.style.visibility =
-                                                'visible';
-                                        } else {
-                                            contentWindow.document.documentElement.style.visibility =
-                                                'hidden';
-                                        }
-                                    });
-                                },
-                                {
-                                    root: target.parentElement,
-                                },
-                            );
-
-                            observer.observe(target);
-
-                            // Have to remove he observer, otherwise we end up
-                            // with conflicting values when a new page is loaded
-                            // in the iframe.
-                            contentWindow.addEventListener('unload', () => {
-                                observer.unobserve(target);
-                            });
-
-                            // And this keeps track of the scroll position.
-                            contentWindow.addEventListener('scroll', () => {
-                                if (contentWindow.scrollY !== 0) {
-                                    // Record the current scroll position.
-                                    // If it is 0, it could be that the iframe
-                                    // has been hidden or the user scrolled
-                                    // there. So we have to ignore 0. But we
-                                    // don't want to be one pixel off if the
-                                    // user really did scroll there, so we
-                                    // assume that if the last scroll is 1, then
-                                    // the user probably went all the way to 0.
-                                    if (contentWindow.scrollY === 1) {
-                                        iframeScroll = 0;
-                                    } else {
-                                        iframeScroll = contentWindow.scrollY;
-                                    }
-                                }
-                            });
-
-                            // Override browser default key bindings in iframe.
-                            contentWindow.document.addEventListener('keydown', (e) => {
-                                // use Ctrl-D/Cmd-D to toggle docs
-                                if (
-                                    (isMacOS()
-                                        ? e.metaKey && !e.ctrlKey
-                                        : e.ctrlKey && !e.metaKey) &&
-                                    !e.altKey &&
-                                    e.key == 'd'
-                                ) {
-                                    e.preventDefault();
-                                    dispatch(toggleBoolean(BooleanSettingId.ShowDocs));
-                                }
-                            });
-
-                            if (document.body.classList.contains(Classes.DARK)) {
-                                contentWindow.document.documentElement.classList.add(
-                                    Classes.DARK,
-                                );
-                            }
-                        }}
-                        src="static/docs/index.html"
-                        allowFullScreen={true}
-                        title="docs"
-                        width="100%"
-                        height="100%"
-                        frameBorder="none"
-                    />
+                    {isDragging && <div className="h-100 w-100 p-absolute" />}
+                    <Docs />
                 </div>
             </SplitterLayout>
             <StatusBar />