Set post editor sidebar tabs to manual activation

packages/edit-post/src/components/sidebar/settings-header/index.js

@@ -4,6 +4,7 @@
 import { privateApis as componentsPrivateApis } from '@wordpress/components';
 import { __, _x } from '@wordpress/i18n';
 import { useSelect } from '@wordpress/data';
+import { forwardRef } from '@wordpress/element';
 import { store as editorStore } from '@wordpress/editor';
 
 /**
@@ -14,7 +15,7 @@ import { sidebars } from '../settings-sidebar';
 
 const { Tabs } = unlock( componentsPrivateApis );
 
-const SettingsHeader = () => {
+const SettingsHeader = ( _, ref ) => {
 	const { documentLabel } = useSelect( ( select ) => {
 		const { getPostTypeLabel } = select( editorStore );
 
@@ -25,14 +26,24 @@ const SettingsHeader = () => {
 	}, [] );
 
 	return (
-		<Tabs.TabList>
-			<Tabs.Tab tabId={ sidebars.document }>{ documentLabel }</Tabs.Tab>
-			<Tabs.Tab tabId={ sidebars.block }>
+		<Tabs.TabList ref={ ref }>
+			<Tabs.Tab
+				tabId={ sidebars.document }
+				// Used for focus management in the SettingsSidebar component.
+				data-tab-id={ sidebars.document }
+			>
+				{ documentLabel }
+			</Tabs.Tab>
+			<Tabs.Tab
+				tabId={ sidebars.block }
+				// Used for focus management in the SettingsSidebar component.
+				data-tab-id={ sidebars.block }
+			>
 				{ /* translators: Text label for the Block Settings Sidebar tab. */ }
 				{ __( 'Block' ) }
 			</Tabs.Tab>
 		</Tabs.TabList>
 	);
 };
 
-export default SettingsHeader;
+export default forwardRef( SettingsHeader );

packages/edit-post/src/components/sidebar/settings-sidebar/index.js

@@ -6,7 +6,13 @@ import {
 	store as blockEditorStore,
 } from '@wordpress/block-editor';
 import { useSelect, useDispatch } from '@wordpress/data';
-import { Platform, useCallback, useContext } from '@wordpress/element';
+import {
+	Platform,
+	useCallback,
+	useContext,
+	useEffect,
+	useRef,
+} from '@wordpress/element';
 import { isRTL, __ } from '@wordpress/i18n';
 import { drawerLeft, drawerRight } from '@wordpress/icons';
 import { store as interfaceStore } from '@wordpress/interface';
@@ -50,17 +56,45 @@ const SidebarContent = ( {
 	keyboardShortcut,
 	isEditingTemplate,
 } ) => {
+	const tabListRef = useRef( null );
 	// Because `PluginSidebarEditPost` renders a `ComplementaryArea`, we
 	// need to forward the `Tabs` context so it can be passed through the
 	// underlying slot/fill.
 	const tabsContextValue = useContext( Tabs.Context );
 
+	// This effect addresses a race condition caused by tabbing from the last
+	// block in the editor into the settings sidebar. Without this effect, the
+	// selected tab and browser focus can become separated in an unexpected way
+	// (e.g the "block" tab is focused, but the "post" tab is selected).
+	useEffect( () => {
+		const tabsElements = Array.from(
+			tabListRef.current?.querySelectorAll( '[role="tab"]' ) || []
+		);
+		const selectedTabElement = tabsElements.find(
+			// We are purposefully using a custom `data-tab-id` attribute here
+			// because we don't want rely on any assumptions about `Tabs`
+			// component internals.
+			( element ) => element.getAttribute( 'data-tab-id' ) === sidebarName
+		);
+		const activeElement = selectedTabElement?.ownerDocument.activeElement;
+		const tabsHasFocus = tabsElements.some( ( element ) => {
+			return activeElement && activeElement.id === element.id;
+		} );
+		if (
+			tabsHasFocus &&
+			selectedTabElement &&
+			selectedTabElement.id !== activeElement?.id
+		) {
+			selectedTabElement?.focus();
+		}
+	}, [ sidebarName ] );
+
 	return (
 		<PluginSidebarEditPost
 			identifier={ sidebarName }
 			header={
 				<Tabs.Context.Provider value={ tabsContextValue }>
-					<SettingsHeader />
+					<SettingsHeader ref={ tabListRef } />
 				</Tabs.Context.Provider>
 			}
 			closeLabel={ __( 'Close Settings' ) }
@@ -157,6 +191,7 @@ const SettingsSidebar = () => {
 			// the selected tab to `null` avoids that.
 			selectedTabId={ isSettingsSidebarActive ? sidebarName : null }
 			onSelect={ onTabSelect }
+			selectOnMove={ false }
 		>
 			<SidebarContent
 				sidebarName={ sidebarName }

test/e2e/specs/editor/various/keyboard-navigable-blocks.spec.js

@@ -75,7 +75,7 @@ test.describe( 'Order of block keyboard navigation', () => {
 		);
 
 		await page.keyboard.press( 'Tab' );
-		await KeyboardNavigableBlocks.expectLabelToHaveFocus( 'Block' );
+		await KeyboardNavigableBlocks.expectLabelToHaveFocus( 'Post' );
 	} );
 
 	test( 'allows tabbing in navigation mode if no block is selected (reverse)', async ( {