fix(Dropdown): opening sub menus in dropdown menu with using keyboard

src/components/DropdownMenu/DropdownMenu.test.tsx

@@ -3,7 +3,12 @@ import React from 'react';
 import {render, screen} from '@testing-library/react';
 import userEvent from '@testing-library/user-event';
 
-import {DropdownMenu} from './DropdownMenu';
+import {DropdownMenu, DropdownMenuItem} from './DropdownMenu';
+
+export const optionsWithSubItems: DropdownMenuItem<unknown>[] = [
+    {text: 'Edit', action: () => {}},
+    {text: 'Other', items: [{action: () => {}, text: 'Submenu'}]},
+];
 
 test('do not trigger `onOpenToggle` on mount', () => {
     const onOpenToggle = jest.fn();
@@ -30,3 +35,20 @@ test('should not trigger on control disable', async () => {
 
     expect(onOpenToggle).not.toHaveBeenCalled();
 });
+
+describe('submenu', () => {
+    test('should open submenu if it presses enter on submenu toggle', async () => {
+        render(<DropdownMenu items={optionsWithSubItems} />);
+
+        const switcher = screen.getByRole('button');
+        await userEvent.click(switcher);
+
+        expect(screen.getByText('Other')).toBeVisible();
+
+        await userEvent.keyboard('[ArrowDown]');
+        await userEvent.keyboard('[ArrowDown]');
+        await userEvent.keyboard('[Enter]');
+
+        expect(screen.getByText('Submenu')).toBeVisible();
+    });
+});

src/components/DropdownMenu/DropdownMenuPopup.tsx

@@ -93,9 +93,14 @@ export const DropdownMenuPopup = <T,>({
                 case 'Enter':
                 case ' ': {
                     const activeItem = items[activeItemIndex];
-                    if (activeItem) {
+                    const isSubmenuToggleActive = activeItem?.items;
+
+                    if (isSubmenu || isSubmenuToggleActive) {
+                        event.stopPropagation();
                         event.preventDefault();
+                    }
 
+                    if (activeItem) {
                         handleSelect(activeItem, event);
                     }