@@ -12,6 +12,10 @@
 
 -   Keep filter and item actions menus dismissible when their triggers become disabled ([#83791](https://github.com/WordPress/gutenberg/pull/83791)).
 
+### Bug Fixes
+
+-   Grid layout: measure the container as the grid attaches rather than waiting for the resize observer's first report, so the grid no longer renders a frame with every item in a full-width column of its own before snapping to its real column count ([#83752](https://github.com/WordPress/gutenberg/pull/83752)).
+
 ### Documentation
 
 -   Document that a custom `sort` receives the field values returned by `getValue`, not the items ([#83483](https://github.com/WordPress/gutenberg/pull/83483)).
 
@@ -7,7 +7,6 @@ import {
 	useRef,
 	useState,
 } from '@wordpress/element';
-import { useResizeObserver } from '@wordpress/compose';
 import { Stack } from '@wordpress/ui';
 import DataViewsContext from '../components/dataviews-context';
 import { VIEW_LAYOUTS } from '../components/dataviews-layouts';
@@ -34,6 +33,7 @@ import DataViewsViewConfig, {
 	ViewTypeMenu,
 } from '../components/dataviews-view-config';
 import normalizeFields from '../field-types';
+import useContainerWidth from '../hooks/use-container-width';
 import useData from '../hooks/use-data';
 import { useInfiniteScroll } from '../hooks/use-infinite-scroll';
 import usePageClamp from '../hooks/use-page-clamp';
@@ -261,15 +261,7 @@ function DataViewsPicker< Item >( {
 		setVisibleEntries?: React.Dispatch< React.SetStateAction< number[] > >;
 	};
 	const containerRef = useRef< HTMLDivElement >( null );
-	const [ containerWidth, setContainerWidth ] = useState( 0 );
-	const resizeObserverRef = useResizeObserver(
-		( resizeObserverEntries: any ) => {
-			setContainerWidth(
-				resizeObserverEntries[ 0 ].borderBoxSize[ 0 ].inlineSize
-			);
-		},
-		{ box: 'border-box' }
-	);
+	const [ containerWidth, resizeObserverRef ] = useContainerWidth();
 	const [ openedFilter, setOpenedFilter ] = useState< string | null >( null );
 	function setSelectionWithChange( value: SelectionOrUpdater ) {
 		const newValue =
 
@@ -6,7 +6,6 @@ import {
 	useRef,
 	useState,
 } from '@wordpress/element';
-import { useResizeObserver } from '@wordpress/compose';
 import { Stack } from '@wordpress/ui';
 import DataViewsContext from '../components/dataviews-context';
 import { VIEW_LAYOUTS } from '../components/dataviews-layouts';
@@ -26,6 +25,7 @@ import DataViewsViewConfig, {
 	ViewTypeMenu,
 } from '../components/dataviews-view-config';
 import normalizeFields from '../field-types';
+import useContainerWidth from '../hooks/use-container-width';
 import useData from '../hooks/use-data';
 import { useInfiniteScroll } from '../hooks/use-infinite-scroll';
 import usePageClamp from '../hooks/use-page-clamp';
@@ -136,15 +136,7 @@ function DataViews< Item >( {
 		setVisibleEntries?: React.Dispatch< React.SetStateAction< number[] > >;
 	};
 	const containerRef = useRef< HTMLDivElement >( null );
-	const [ containerWidth, setContainerWidth ] = useState( 0 );
-	const resizeObserverRef = useResizeObserver(
-		( resizeObserverEntries: any ) => {
-			setContainerWidth(
-				resizeObserverEntries[ 0 ].borderBoxSize[ 0 ].inlineSize
-			);
-		},
-		{ box: 'border-box' }
-	);
+	const [ containerWidth, resizeObserverRef ] = useContainerWidth();
 	const [ openedFilter, setOpenedFilter ] = useState< string | null >( null );
 	function setSelectionWithChange( value: SelectionOrUpdater ) {
 		const newValue =
 
@@ -0,0 +1,79 @@
+import { screen, waitFor } from '@testing-library/react';
+import { render } from 'vitest-browser-react';
+import { describe, expect, it } from 'vitest';
+import { useLayoutEffect } from '@wordpress/element';
+import DataViews from '../index';
+import { LAYOUT_GRID } from '../../constants';
+import type { View } from '../../types';
+
+type Data = {
+	id: number;
+	title: string;
+};
+
+const view: View = {
+	type: LAYOUT_GRID,
+	search: '',
+	page: 1,
+	perPage: 10,
+	layout: {},
+	filters: [],
+	fields: [ 'title' ],
+	titleField: 'title',
+};
+
+const data: Data[] = [
+	{ id: 1, title: 'First item' },
+	{ id: 2, title: 'Second item' },
+	{ id: 3, title: 'Third item' },
+];
+
+// Counts the grid rows in the first animation frame after mount. Animation
+// frame callbacks run before resize observer callbacks, so this is the layout
+// the browser paints first.
+function FirstFrameRowCount( {
+	onCount,
+}: {
+	onCount: ( count: number ) => void;
+} ) {
+	useLayoutEffect( () => {
+		requestAnimationFrame( () => {
+			onCount( screen.queryAllByRole( 'row' ).length );
+		} );
+	}, [ onCount ] );
+	return null;
+}
+
+describe( 'DataViews grid columns', () => {
+	it( 'paints the grid at its real column count on the first frame', async () => {
+		let firstFrameRowCount: number | undefined;
+
+		// A 600px wide container fits two columns at the default 230px preview
+		// size, so the three items render as two rows.
+		await render(
+			<div style={ { width: 600 } }>
+				<DataViews< Data >
+					view={ view }
+					onChangeView={ () => {} }
+					fields={ [ { id: 'title', label: 'Title', type: 'text' } ] }
+					data={ data }
+					getItemId={ ( item ) => item.id.toString() }
+					paginationInfo={ { totalItems: 3, totalPages: 1 } }
+					defaultLayouts={ { [ LAYOUT_GRID ]: true } }
+				/>
+				<FirstFrameRowCount
+					onCount={ ( count ) => {
+						if ( firstFrameRowCount === undefined ) {
+							firstFrameRowCount = count;
+						}
+					} }
+				/>
+			</div>
+		);
+
+		await waitFor( () => expect( firstFrameRowCount ).toBe( 2 ) );
+
+		// The observer reports the same width, so nothing changes.
+		expect( screen.getAllByRole( 'row' ) ).toHaveLength( 2 );
+	} );
+} );
@@ -1,3 +1,4 @@
+export { default as useContainerWidth } from './use-container-width';
 export { default as useFormValidity } from './use-form-validity';
 export { default as useData } from './use-data';
 export { useInfiniteScroll } from './use-infinite-scroll';
 
@@ -0,0 +1,39 @@
+import { useCallback, useState } from '@wordpress/element';
+import { useMergeRefs, useResizeObserver } from '@wordpress/compose';
+
+/**
+ * Tracks the width of the element the returned ref is attached to.
+ *
+ * The element is measured when it attaches, so a width is available for the
+ * first paint. The resize observer keeps the width up to date from then on.
+ *
+ * Detaching leaves the last width in place; reattaching measures again.
+ *
+ * @return The element's width, and the ref to attach to it.
+ */
+export default function useContainerWidth< T extends HTMLElement >(): [
+	number,
+	( element?: T | null ) => void,
+] {
+	const [ width, setWidth ] = useState( 0 );
+
+	// `inlineSize` is only available on an observer entry, so it can't be read
+	// here. `offsetWidth` reports the same border box and, like
+	// `borderBoxSize`, is unaffected by transforms.
+	const measureRef = useCallback( ( element?: T | null ) => {
+		if ( element ) {
+			setWidth( element.offsetWidth );
+		}
+	}, [] );
+
+	const observerRef = useResizeObserver< T >(
+		( entries ) => {
+			setWidth(
+				Math.floor( entries[ 0 ].borderBoxSize[ 0 ].inlineSize )
+			);
+		},
+		{ box: 'border-box' }
+	);
+
+	return [ width, useMergeRefs( [ measureRef, observerRef ] ) ];
+}
Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,4 @@`
	`1`	`+export { default as useContainerWidth } from './use-container-width';`
`1`	`2`	`export { default as useFormValidity } from './use-form-validity';`
`2`	`3`	`export { default as useData } from './use-data';`
`3`	`4`	`export { useInfiniteScroll } from './use-infinite-scroll';`