diff --git a/package-lock.json b/package-lock.json
index 9b0cd4a7d26ce..0a22ec44ba718 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -17330,7 +17330,6 @@
 				"@wordpress/shortcode": "file:packages/shortcode",
 				"@wordpress/token-list": "file:packages/token-list",
 				"@wordpress/url": "file:packages/url",
-				"@wordpress/warning": "file:packages/warning",
 				"@wordpress/wordcount": "file:packages/wordcount",
 				"classnames": "^2.2.5",
 				"css-mediaquery": "^0.1.2",
@@ -17341,7 +17340,6 @@
 				"memize": "^1.1.0",
 				"react-autosize-textarea": "^7.1.0",
 				"react-spring": "^8.0.19",
-				"react-transition-group": "^2.9.0",
 				"reakit": "1.1.0",
 				"redux-multi": "^0.1.12",
 				"refx": "^3.0.0",
@@ -32480,6 +32478,7 @@
 			"version": "3.4.0",
 			"resolved": "https://registry.npmjs.org/dom-helpers/-/dom-helpers-3.4.0.tgz",
 			"integrity": "sha512-LnuPJ+dwqKDIyotW1VzmOZ5TONUN7CwkCR5hrgawTUbkBGYdeoNLZo6nNfGkCrjtE1nXXaj7iMMpDa8/d9WoIA==",
+			"dev": true,
 			"requires": {
 				"@babel/runtime": "^7.1.2"
 			}
@@ -53532,7 +53531,8 @@
 		"react-lifecycles-compat": {
 			"version": "3.0.4",
 			"resolved": "https://registry.npmjs.org/react-lifecycles-compat/-/react-lifecycles-compat-3.0.4.tgz",
-			"integrity": "sha512-fBASbA6LnOU9dOU2eW7aQ8xmYBSXUIWr+UmF9b1efZBazGNO+rcXT/icdKnYm2pTwcRylVUYwW7H1PHfLekVzA=="
+			"integrity": "sha512-fBASbA6LnOU9dOU2eW7aQ8xmYBSXUIWr+UmF9b1efZBazGNO+rcXT/icdKnYm2pTwcRylVUYwW7H1PHfLekVzA==",
+			"dev": true
 		},
 		"react-merge-refs": {
 			"version": "1.0.0",
@@ -54811,6 +54811,7 @@
 			"version": "2.9.0",
 			"resolved": "https://registry.npmjs.org/react-transition-group/-/react-transition-group-2.9.0.tgz",
 			"integrity": "sha512-+HzNTCHpeQyl4MJ/bdE0u6XRMe9+XG/+aL4mCxVN4DnPBQ0/5bfHWPDuOZUzYdMj94daZaZdCCc1Dzt9R/xSSg==",
+			"dev": true,
 			"requires": {
 				"dom-helpers": "^3.4.0",
 				"loose-envify": "^1.4.0",
diff --git a/packages/block-editor/package.json b/packages/block-editor/package.json
index b8264cfd2e8ee..e5e7a8a50cee6 100644
--- a/packages/block-editor/package.json
+++ b/packages/block-editor/package.json
@@ -50,7 +50,6 @@
 		"@wordpress/shortcode": "file:../shortcode",
 		"@wordpress/token-list": "file:../token-list",
 		"@wordpress/url": "file:../url",
-		"@wordpress/warning": "file:../warning",
 		"@wordpress/wordcount": "file:../wordcount",
 		"classnames": "^2.2.5",
 		"css-mediaquery": "^0.1.2",
@@ -61,7 +60,6 @@
 		"memize": "^1.1.0",
 		"react-autosize-textarea": "^7.1.0",
 		"react-spring": "^8.0.19",
-		"react-transition-group": "^2.9.0",
 		"reakit": "1.1.0",
 		"redux-multi": "^0.1.12",
 		"refx": "^3.0.0",
diff --git a/packages/block-editor/src/components/block-controls/index.js b/packages/block-editor/src/components/block-controls/index.js
index f2b35e4b5301f..297d3839df4aa 100644
--- a/packages/block-editor/src/components/block-controls/index.js
+++ b/packages/block-editor/src/components/block-controls/index.js
@@ -20,24 +20,18 @@ import useDisplayBlockControls from '../use-display-block-controls';
 
 const { Fill, Slot } = createSlotFill( 'BlockControls' );
 
-function BlockControlsSlot( { __experimentalIsExpanded = false, ...props } ) {
+function BlockControlsSlot( props ) {
 	const accessibleToolbarState = useContext( ToolbarContext );
-	return (
-		<Slot
-			name={ buildSlotName( __experimentalIsExpanded ) }
-			{ ...props }
-			fillProps={ accessibleToolbarState }
-		/>
-	);
+	return <Slot { ...props } fillProps={ accessibleToolbarState } />;
 }
 
-function BlockControlsFill( { controls, __experimentalIsExpanded, children } ) {
+function BlockControlsFill( { controls, children } ) {
 	if ( ! useDisplayBlockControls() ) {
 		return null;
 	}
 
 	return (
-		<Fill name={ buildSlotName( __experimentalIsExpanded ) }>
+		<Fill>
 			{ ( fillProps ) => {
 				// Children passed to BlockControlsFill will not have access to any
 				// React Context whose Provider is part of the BlockControlsSlot tree.
@@ -54,9 +48,6 @@ function BlockControlsFill( { controls, __experimentalIsExpanded, children } ) {
 	);
 }
 
-const buildSlotName = ( isExpanded ) =>
-	`BlockControls${ isExpanded ? '-expanded' : '' }`;
-
 const BlockControls = BlockControlsFill;
 
 BlockControls.Slot = BlockControlsSlot;
diff --git a/packages/block-editor/src/components/block-toolbar/expanded-block-controls-container.js b/packages/block-editor/src/components/block-toolbar/expanded-block-controls-container.js
deleted file mode 100644
index e1a475c286e88..0000000000000
--- a/packages/block-editor/src/components/block-toolbar/expanded-block-controls-container.js
+++ /dev/null
@@ -1,131 +0,0 @@
-/**
- * External dependencies
- */
-import { TransitionGroup, CSSTransition } from 'react-transition-group';
-import { throttle } from 'lodash';
-
-/**
- * WordPress dependencies
- */
-import { useRef, useState, useEffect, useCallback } from '@wordpress/element';
-import warning from '@wordpress/warning';
-
-/**
- * Internal dependencies
- */
-import BlockControls from '../block-controls';
-
-function getComputedStyle( node ) {
-	return node.ownerDocument.defaultView.getComputedStyle( node );
-}
-
-export default function ExpandedBlockControlsContainer( {
-	children,
-	className,
-} ) {
-	return (
-		<BlockControls.Slot __experimentalIsExpanded>
-			{ ( fills ) => {
-				return (
-					<ExpandedBlockControlsHandler
-						className={ className }
-						fills={ fills }
-					>
-						{ children }
-					</ExpandedBlockControlsHandler>
-				);
-			} }
-		</BlockControls.Slot>
-	);
-}
-
-function ExpandedBlockControlsHandler( { fills, className = '', children } ) {
-	const containerRef = useRef();
-	const fillsRef = useRef();
-	const toolbarRef = useRef();
-	const [ dimensions, setDimensions ] = useState( {} );
-
-	const fillsPropRef = useRef();
-	fillsPropRef.current = fills;
-	const resizeToolbar = useCallback(
-		throttle( () => {
-			const toolbarContentElement = fillsPropRef.current.length
-				? fillsRef.current
-				: toolbarRef.current;
-			if ( ! toolbarContentElement ) {
-				return;
-			}
-			toolbarContentElement.style.position = 'absolute';
-			toolbarContentElement.style.width = 'auto';
-			const contentCSS = getComputedStyle( toolbarContentElement );
-			setDimensions( {
-				width: contentCSS.getPropertyValue( 'width' ),
-				height: contentCSS.getPropertyValue( 'height' ),
-			} );
-			toolbarContentElement.style.position = '';
-			toolbarContentElement.style.width = '';
-		}, 100 ),
-		[]
-	);
-
-	useEffect( () => {
-		const observer = new window.MutationObserver( function (
-			mutationsList
-		) {
-			const hasChildList = mutationsList.find(
-				( { type } ) => type === 'childList'
-			);
-			if ( hasChildList ) {
-				resizeToolbar();
-			}
-		} );
-
-		observer.observe( containerRef.current, {
-			childList: true,
-			subtree: true,
-		} );
-
-		return () => observer.disconnect();
-	}, [] );
-
-	useEffect( () => {
-		if ( fills.length > 1 ) {
-			warning(
-				`${ fills.length } <BlockControls isExpanded> slots were registered but only one may be displayed.`
-			);
-		}
-	}, [ fills.length ] );
-
-	const displayFill = fills[ 0 ];
-	return (
-		<div
-			className="block-editor-block-toolbar-animated-width-container"
-			ref={ containerRef }
-			style={ dimensions }
-		>
-			<TransitionGroup>
-				{ displayFill ? (
-					<CSSTransition
-						key="fills"
-						timeout={ 300 }
-						classNames="block-editor-block-toolbar-content"
-					>
-						<div className={ className } ref={ fillsRef }>
-							{ displayFill }
-						</div>
-					</CSSTransition>
-				) : (
-					<CSSTransition
-						key="default"
-						timeout={ 300 }
-						classNames="block-editor-block-toolbar-content"
-					>
-						<div className={ className } ref={ toolbarRef }>
-							{ children }
-						</div>
-					</CSSTransition>
-				) }
-			</TransitionGroup>
-		</div>
-	);
-}
diff --git a/packages/block-editor/src/components/block-toolbar/index.js b/packages/block-editor/src/components/block-toolbar/index.js
index bed8b921a2fe9..87cfcad1cf9f1 100644
--- a/packages/block-editor/src/components/block-toolbar/index.js
+++ b/packages/block-editor/src/components/block-toolbar/index.js
@@ -22,12 +22,8 @@ import BlockControls from '../block-controls';
 import BlockFormatControls from '../block-format-controls';
 import BlockSettingsMenu from '../block-settings-menu';
 import { useShowMoversGestures } from './utils';
-import ExpandedBlockControlsContainer from './expanded-block-controls-container';
 
-export default function BlockToolbar( {
-	hideDragHandle,
-	__experimentalExpandedControl = false,
-} ) {
+export default function BlockToolbar( { hideDragHandle } ) {
 	const {
 		blockClientIds,
 		blockClientId,
@@ -106,12 +102,8 @@ export default function BlockToolbar( {
 		shouldShowMovers && 'is-showing-movers'
 	);
 
-	const Wrapper = __experimentalExpandedControl
-		? ExpandedBlockControlsContainer
-		: 'div';
-
 	return (
-		<Wrapper className={ classes }>
+		<div className={ classes }>
 			<div ref={ nodeRef } { ...showMoversGestures }>
 				{ ! isMultiToolbar && (
 					<div className="block-editor-block-toolbar__block-parent-selector-wrapper">
@@ -141,6 +133,6 @@ export default function BlockToolbar( {
 				</>
 			) }
 			<BlockSettingsMenu clientIds={ blockClientIds } />
-		</Wrapper>
+		</div>
 	);
 }
diff --git a/packages/block-editor/src/components/block-toolbar/style.scss b/packages/block-editor/src/components/block-toolbar/style.scss
index bffe229b714e0..c9499b4731dfd 100644
--- a/packages/block-editor/src/components/block-toolbar/style.scss
+++ b/packages/block-editor/src/components/block-toolbar/style.scss
@@ -106,31 +106,3 @@
 		transform: translateY(-($block-toolbar-height + $grid-unit-15));
 	}
 }
-
-.block-editor-block-toolbar-animated-width-container {
-	position: relative;
-	overflow: hidden;
-	transition: width 300ms;
-}
-
-.block-editor-block-toolbar-content-enter {
-	position: absolute;
-	top: 0;
-	left: 0;
-	width: auto;
-	opacity: 0;
-}
-.block-editor-block-toolbar-content-enter-active {
-	position: absolute;
-	opacity: 1;
-	transition: opacity 300ms;
-}
-.block-editor-block-toolbar-content-exit {
-	width: auto;
-	opacity: 1;
-	pointer-events: none;
-}
-.block-editor-block-toolbar-content-exit-active {
-	opacity: 0;
-	transition: opacity 300ms;
-}