Fix behavior of renderAppender when standalone

packages/block-library/form/edit/standalone-form.js

@@ -4,6 +4,7 @@
 import {
 	useBlockProps,
 	useInnerBlocksProps,
+	InnerBlocks,
 	Warning,
 	store as blockEditorStore,
 } from '@wordpress/block-editor';
@@ -155,30 +156,37 @@ export default function StandaloneForm( blockObject ) {
 		clientId,
 	} = blockObject;
 
-	const blockProps = useBlockProps( {
-		className: 'block-library-block__reusable-block-container',
-	} );
-
-	const innerBlockProps = useInnerBlocksProps( blockProps, {
-		allowedBlocks: ALLOWED_BLOCKS,
-		template: TEMPLATE,
-	} );
-
-	const isNested = useSelect(
+	const { isNested, hasInnerBlocks } = useSelect(
 		( select ) => {
 			const {
 				getBlockParents,
 				getBlock,
+				getBlockCount,
 			} = select( blockEditorStore );
 
 			const parentBlocks = getBlockParents( clientId );
 			const rootBlock = getBlock( parentBlocks[ 0 ] );
 
-			return rootBlock?.name === name;
+			return {
+				isNested: rootBlock?.name === name,
+				hasInnerBlocks: getBlockCount( clientId ) > 0,
+			};
 		},
 		[ clientId, name ]
 	);
 
+	const blockProps = useBlockProps( {
+		className: 'block-library-block__reusable-block-container',
+	} );
+
+	const innerBlockProps = useInnerBlocksProps( blockProps, {
+		allowedBlocks: ALLOWED_BLOCKS,
+		template: TEMPLATE,
+		renderAppender: hasInnerBlocks
+			? undefined
+			: InnerBlocks.ButtonBlockAppender,
+	} );
+
 	if ( isNested ) {
 		return (
 			<div { ...blockProps }>