Remove block movers if there is only one item

editor/components/block-mover/index.js

@@ -46,10 +46,16 @@ export class BlockMover extends Component {
 		const { onMoveUp, onMoveDown, isFirst, isLast, uids, blockType, firstIndex, isLocked, instanceId, isHidden } = this.props;
 		const { isFocused } = this.state;
 		const blocksCount = castArray( uids ).length;
+
 		if ( isLocked ) {
 			return null;
 		}
 
+		// Don't render if there's only one block in the list.
+		if ( isFirst && isLast ) {
+			return null;
+		}
+
 		// We emulate a disabled state because forcefully applying the `disabled`
 		// attribute on the button while it has focus causes the screen to change
 		// to an unfocused state (body as active element) without firing blur on,