From 23f812f8d5468978d556a090d11b653aadcddd15 Mon Sep 17 00:00:00 2001
From: ramonjd <ramonjd@gmail.com>
Date: Mon, 18 Oct 2021 13:18:46 +1100
Subject: [PATCH] The `href` attribute triggers the browser's native HTML drag
 operations. When the link is dragged, the element's outerHTML is set in
 DataTransfer object as text/html. We need to clear any HTML drag data to
 prevent `pasteHandler` from calling inside `useOnBlockDrop`.

---
 .../components/list-view/block-select-button.js   | 15 ++++++++++-----
 .../various/block-hierarchy-navigation.test.js    |  2 +-
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/packages/block-editor/src/components/list-view/block-select-button.js b/packages/block-editor/src/components/list-view/block-select-button.js
index a3fb99582edecc..303c1ddc4a70f0 100644
--- a/packages/block-editor/src/components/list-view/block-select-button.js
+++ b/packages/block-editor/src/components/list-view/block-select-button.js
@@ -46,9 +46,14 @@ function ListViewBlockSelectButton(
 		siblingBlockCount,
 		level
 	);
-	const onClickHandler = ( event ) => {
-		onClick();
-		event.preventDefault();
+
+	// The `href` attribute triggers the browser's native HTML drag operations.
+	// When the link is dragged, the element's outerHTML is set in DataTransfer object as text/html.
+	// We need to clear any HTML drag data to prevent `pasteHandler` from firing
+	// inside the `useOnBlockDrop` hook.
+	const onDragStartHandler = ( event ) => {
+		event.dataTransfer.clearData();
+		onDragStart( event );
 	};
 
 	return (
@@ -58,12 +63,12 @@ function ListViewBlockSelectButton(
 					'block-editor-list-view-block-select-button',
 					className
 				) }
-				onClick={ onClickHandler }
+				onClick={ onClick }
 				aria-describedby={ descriptionId }
 				ref={ ref }
 				tabIndex={ tabIndex }
 				onFocus={ onFocus }
-				onDragStart={ onDragStart }
+				onDragStart={ onDragStartHandler }
 				onDragEnd={ onDragEnd }
 				draggable={ draggable }
 				href={ `#block-${ clientId }` }
diff --git a/packages/e2e-tests/specs/editor/various/block-hierarchy-navigation.test.js b/packages/e2e-tests/specs/editor/various/block-hierarchy-navigation.test.js
index fd4de7ba31d320..69611a0eebfd9d 100644
--- a/packages/e2e-tests/specs/editor/various/block-hierarchy-navigation.test.js
+++ b/packages/e2e-tests/specs/editor/various/block-hierarchy-navigation.test.js
@@ -155,7 +155,7 @@ describe( 'Navigating the block hierarchy', () => {
 		// Return to first block.
 		await openListViewSidebar();
 		await page.keyboard.press( 'ArrowUp' );
-		await page.keyboard.press( 'Space' );
+		await page.keyboard.press( 'Enter' );
 
 		// Replace its content.
 		await pressKeyWithModifier( 'primary', 'a' );