@@ -17,15 +17,6 @@
 	}
 }
 
-.block-editor-hooks__position-control-item {
-
-	/**
-	 * Try to make items match the width of the anchor, subtract any margin on
-	 * items to calculate the correct inner width.
-	 */
-	max-inline-size: max(calc(var(--anchor-width) - (2 * var(--wp-ui-popup-padding))), 223px);
-}
-
 .block-editor-hooks__position-control-item-hint {
 	color: var(--wpds-color-foreground-content-neutral-weak);
 	margin-block-start: $grid-unit-05;
 
@@ -261,6 +261,7 @@ export function PositionPanelPure( {
 				label={ __( 'Position' ) }
 				hideLabelFromVision
 				description={ stickyHelpText }
+				popupWidth="anchor"
 				items={ options }
 				value={ selectedOption }
 				onValueChange={ ( selectedItem ) => {
@@ -277,7 +278,6 @@ export function PositionPanelPure( {
 							key={ option.key }
 							value={ option }
 							label={ option.label }
-							className="block-editor-hooks__position-control-item"
 							aria-describedby={ hintId }
 						>
 							<div>{ option.label }</div>
 
@@ -6,6 +6,10 @@
 
 -   `Popover`: Widen `offset` to also accept an object with separate main and cross axis offsets. The same applies to `BorderBoxControl`'s `popoverOffset` prop ([#82060](https://github.com/WordPress/gutenberg/pull/82060)).
 
+### Bug Fixes
+
+-   `Snackbar`: Restart the auto-dismiss timer when a notice is recreated with the same ID during removal ([#81764](https://github.com/WordPress/gutenberg/pull/81764)).
+
 ### Internal
 
 -   Use the `.jsx` extension for JavaScript source files that contain JSX ([#80990](https://github.com/WordPress/gutenberg/pull/80990)).
 
@@ -1,5 +1,6 @@
 import type { ForwardedRef, KeyboardEvent, MouseEvent } from 'react';
 import clsx from 'clsx';
+import { useIsPresent } from 'framer-motion';
 import { speak } from '@wordpress/a11y';
 import {
 	useEffect,
@@ -57,6 +58,8 @@ function UnforwardedSnackbar(
 	}: WordPressComponentProps< SnackbarProps, 'div' >,
 	ref: ForwardedRef< any >
 ) {
+	const isPresent = useIsPresent();
+
 	function dismissMe( event: KeyboardEvent | MouseEvent ) {
 		if ( event && event.preventDefault ) {
 			event.preventDefault();
@@ -92,16 +95,17 @@ function UnforwardedSnackbar(
 	} );
 
 	useEffect( () => {
-		// Only set up the timeout dismiss if we're not explicitly dismissing.
+		if ( explicitDismiss || ! isPresent ) {
+			return;
+		}
+
 		const timeoutHandle = setTimeout( () => {
-			if ( ! explicitDismiss ) {
-				callbacksRef.current.onDismiss?.();
-				callbacksRef.current.onRemove?.();
-			}
+			callbacksRef.current.onDismiss?.();
+			callbacksRef.current.onRemove?.();
 		}, NOTICE_TIMEOUT );
 
 		return () => clearTimeout( timeoutHandle );
-	}, [ explicitDismiss ] );
+	}, [ explicitDismiss, isPresent ] );
 
 	const classes = clsx( className, 'components-snackbar', {
 		'components-snackbar-explicit-dismiss': !! explicitDismiss,
 
@@ -1,4 +1,4 @@
-import { render, screen, within } from '@testing-library/react';
+import { act, fireEvent, render, screen, within } from '@testing-library/react';
 import { click } from '@ariakit/test';
 import { speak } from '@wordpress/a11y';
 import { SVG, Path } from '@wordpress/primitives';
@@ -14,6 +14,10 @@ describe( 'Snackbar', () => {
 		mockedSpeak.mockReset();
 	} );
 
+	afterEach( () => {
+		jest.useRealTimers();
+	} );
+
 	it( 'should render correctly', () => {
 		render( <Snackbar>Message</Snackbar> );
 
@@ -44,6 +48,22 @@ describe( 'Snackbar', () => {
 		expect( icon ).toBeVisible();
 	} );
 
+	it( 'should not restart auto-dismissal after an unrelated rerender', async () => {
+		jest.useFakeTimers();
+		const removeNotice = jest.fn();
+		const { rerender } = render(
+			<Snackbar onRemove={ () => removeNotice() }>Message</Snackbar>
+		);
+
+		await act( async () => jest.advanceTimersByTime( 5000 ) );
+		rerender(
+			<Snackbar onRemove={ () => removeNotice() }>Message</Snackbar>
+		);
+		await act( async () => jest.advanceTimersByTime( 1000 ) );
+
+		expect( removeNotice ).toHaveBeenCalledTimes( 1 );
+	} );
+
 	it( 'should be dismissible by clicking the snackbar', async () => {
 		const onRemove = jest.fn();
 		const onDismiss = jest.fn();
@@ -69,6 +89,7 @@ describe( 'Snackbar', () => {
 	} );
 
 	it( 'should not be dismissible by clicking the snackbar when the `explicitDismiss` prop is set to `true`', async () => {
+		jest.useFakeTimers();
 		const onRemove = jest.fn();
 		const onDismiss = jest.fn();
 
@@ -93,7 +114,12 @@ describe( 'Snackbar', () => {
 			'components-snackbar-explicit-dismiss'
 		);
 
-		await click( snackbar );
+		fireEvent.click( snackbar );
+
+		expect( onRemove ).not.toHaveBeenCalled();
+		expect( onDismiss ).not.toHaveBeenCalled();
+
+		await act( async () => jest.advanceTimersByTime( 6000 ) );
 
 		expect( onRemove ).not.toHaveBeenCalled();
 		expect( onDismiss ).not.toHaveBeenCalled();
 
@@ -1,12 +1,19 @@
-import { render, screen } from '@testing-library/react';
+import { act, render, screen } from '@testing-library/react';
 import { click } from '@ariakit/test';
+import { useEffect, useState } from '@wordpress/element';
 import SnackbarList from '../list';
 
+jest.mock( '@wordpress/compose', () => ( {
+	...jest.requireActual( '@wordpress/compose' ),
+	useReducedMotion: () => false,
+} ) );
+
 window.scrollTo = jest.fn();
 
 describe( 'SnackbarList', () => {
 	afterEach( () => {
 		jest.resetAllMocks();
+		jest.useRealTimers();
 	} );
 
 	it( 'should get focus after a snackbar is dismissed', async () => {
@@ -36,4 +43,57 @@ describe( 'SnackbarList', () => {
 
 		expect( screen.getByTestId( 'snackbar-list' ) ).toHaveFocus();
 	} );
+
+	it( 'should restart auto-dismissal when a notice is replaced with the same ID', async () => {
+		jest.useFakeTimers();
+		const onRemove = jest.fn();
+		const notice = {
+			id: 'ID_1',
+			content: 'A collaborator joined.',
+		};
+
+		function RecreatedNotice() {
+			const [ notices, setNotices ] = useState( [ notice ] );
+			const [ shouldRecreate, setShouldRecreate ] = useState( false );
+
+			useEffect( () => {
+				if ( ! shouldRecreate ) {
+					return;
+				}
+
+				const timeoutHandle = setTimeout( () => {
+					setNotices( [ { ...notice } ] );
+					setShouldRecreate( false );
+				}, 50 );
+
+				return () => clearTimeout( timeoutHandle );
+			}, [ shouldRecreate ] );
+
+			return (
+				<SnackbarList
+					notices={ notices }
+					onRemove={ ( id ) => {
+						onRemove( id );
+						setNotices( [] );
+						setShouldRecreate( true );
+					} }
+				/>
+			);
+		}
+
+		render( <RecreatedNotice /> );
+
+		await act( async () => jest.advanceTimersByTime( 6000 ) );
+		expect( onRemove ).toHaveBeenCalledTimes( 1 );
+
+		// Recreate the notice before its 100ms exit animation completes.
+		await act( async () => jest.advanceTimersByTime( 50 ) );
+
+		expect( screen.getByTestId( 'snackbar' ) ).toHaveTextContent(
+			notice.content
+		);
+
+		await act( async () => jest.advanceTimersByTime( 6000 ) );
+		expect( onRemove ).toHaveBeenCalledTimes( 2 );
+	} );
 } );
@@ -4,12 +4,17 @@
 
 ### Breaking Changes
 
+-   `Autocomplete.Popup`, `Combobox.Popup`, `Select.Popup`, `SearchableChipSelect`, and `SearchableChipSelectControl`: The popup now defaults to a fixed anchor width. Use `popupWidth="content"` to restore content-sized width between the anchor and available viewport bounds ([#82087](https://github.com/WordPress/gutenberg/pull/82087)).
 -   Portaled overlays (`AlertDialog`, `Autocomplete`, `Combobox`, `Dialog`, `Drawer`, `Menu`, `Popover`, and `Select`) now inherit the theme from their portal destination instead of re-emitting the trigger's nearest contextual theme. Default portals use the document root theme; custom portal containers use their DOM ancestry ([#82038](https://github.com/WordPress/gutenberg/pull/82038)).
 
 ### New Features
 
 -   Add `Field.VisualLabel` for a purely visual label outside `Field.Root` ([#82095](https://github.com/WordPress/gutenberg/pull/82095)).
 
+### Enhancements
+
+-   `Autocomplete.Popup`, `Combobox.Popup`, `SearchableChipSelect`, `SearchableChipSelectControl`, `Select.Popup`, and `SelectControl`: Add `popupWidth` prop with preset width constraints (`anchor`, `content`, `sm`, `md`, `lg`, and `available`) for the item popup. `SelectControl` defaults to `content` to preserve prior popup sizing ([#82087](https://github.com/WordPress/gutenberg/pull/82087)).
+
 ## 0.21.0 (2026-08-26)
 
 ### New Features
 
@@ -3,16 +3,24 @@ import clsx from 'clsx';
 import { forwardRef } from '@wordpress/element';
 import { renderSlotWithChildren } from '../../../utils/render-slot-with-children';
 import itemPopupStyles from '../../../utils/css/item-popup.module.css';
+import { getItemPopupWidthClassName } from '../../../utils/css/item-popup';
 import { Portal } from './portal';
 import { Positioner } from './positioner';
 import type { AutocompletePopupProps } from './types';
 
 export const Popup = forwardRef< HTMLDivElement, AutocompletePopupProps >(
-	function Popup( { className, portal, positioner, ...restProps }, ref ) {
+	function Popup(
+		{ className, portal, positioner, popupWidth, ...restProps },
+		ref
+	) {
 		const popupContent = (
 			<_Autocomplete.Popup
 				ref={ ref }
-				className={ clsx( itemPopupStyles.popup, className ) }
+				className={ clsx(
+					itemPopupStyles.popup,
+					getItemPopupWidthClassName( popupWidth ),
+					className
+				) }
 				{ ...restProps }
 			/>
 		);
 
@@ -1,6 +1,7 @@
 import type { Autocomplete as _Autocomplete } from '@base-ui/react/autocomplete';
 import type { ReactElement } from 'react';
 import type { ComponentProps } from '../../../utils/types';
+import type { ItemPopupWidthProps } from '../../../utils/css/item-popup';
 
 export type AutocompleteCollectionProps = _Autocomplete.Collection.Props;
 
@@ -61,24 +62,25 @@ export type AutocompleteListBodyProps = ComponentProps< 'div' > & {
 
 export type AutocompletePopupProps = ComponentProps<
 	typeof _Autocomplete.Popup
-> & {
-	children?: React.ReactNode;
-	/**
-	 * Optional portal element, typically `<Autocomplete.Portal />` with custom
-	 * `container`. When omitted, `Autocomplete.Popup` uses
-	 * `Autocomplete.Portal` with default props. Do not pass `children` on the
-	 * portal element; they would be ignored.
-	 */
-	portal?: ReactElement< Omit< PortalProps, 'children' > >;
-	/**
-	 * Optional positioner element, typically `<Autocomplete.Positioner />`
-	 * with custom positioning props (`side`, `align`, `sideOffset`, collision
-	 * settings, etc.). When omitted, `Autocomplete.Popup` uses
-	 * `Autocomplete.Positioner` with default props. Do not pass `children` on
-	 * the positioner element; they would be ignored.
-	 */
-	positioner?: ReactElement< Omit< PositionerProps, 'children' > >;
-};
+> &
+	ItemPopupWidthProps & {
+		children?: React.ReactNode;
+		/**
+		 * Optional portal element, typically `<Autocomplete.Portal />` with custom
+		 * `container`. When omitted, `Autocomplete.Popup` uses
+		 * `Autocomplete.Portal` with default props. Do not pass `children` on the
+		 * portal element; they would be ignored.
+		 */
+		portal?: ReactElement< Omit< PortalProps, 'children' > >;
+		/**
+		 * Optional positioner element, typically `<Autocomplete.Positioner />`
+		 * with custom positioning props (`side`, `align`, `sideOffset`, collision
+		 * settings, etc.). When omitted, `Autocomplete.Popup` uses
+		 * `Autocomplete.Positioner` with default props. Do not pass `children` on
+		 * the positioner element; they would be ignored.
+		 */
+		positioner?: ReactElement< Omit< PositionerProps, 'children' > >;
+	};
 
 export type AutocompleteRootProps< Value = unknown > =
 	_Autocomplete.Root.Props< Value >;
 
@@ -5,14 +5,22 @@ import { Portal } from './portal';
 import { Positioner } from './positioner';
 import { renderSlotWithChildren } from '../../../utils/render-slot-with-children';
 import itemPopupStyles from '../../../utils/css/item-popup.module.css';
+import { getItemPopupWidthClassName } from '../../../utils/css/item-popup';
 import type { ComboboxPopupProps } from './types';
 
 export const Popup = forwardRef< HTMLDivElement, ComboboxPopupProps >(
-	function Popup( { className, portal, positioner, ...restProps }, ref ) {
+	function Popup(
+		{ className, portal, positioner, popupWidth, ...restProps },
+		ref
+	) {
 		const popupContent = (
 			<_Combobox.Popup
 				ref={ ref }
-				className={ clsx( itemPopupStyles.popup, className ) }
+				className={ clsx(
+					itemPopupStyles.popup,
+					getItemPopupWidthClassName( popupWidth ),
+					className
+				) }
 				{ ...restProps }
 			/>
 		);