Bug - [Menu] - Flyout stays open when hovering a disabled item

Describe the problem

In a Menu with containsFlyout, a flyout submenu stays open after the pointer moves from the flyout trigger onto a disabled item.

Hovering an enabled item without a flyout correctly calls setFlyoutRef(null). Disabled items never get that hover:

1. isDisabled: .pf-v6-c-menu__list-item.pf-m-disabled has pointer-events: none, so onMouseOver does not fire.
2. isAriaDisabled: MenuItem skips onMouseOver when isAriaDisabled is true, so setFlyoutRef(null) never runs.

How do you reproduce the problem?

3. Open a Menu with containsFlyout.
4. Include a flyout item, then a disabled item (isDisabled or isAriaDisabled) immediately after it.
5. Hover the flyout item until the submenu opens.
6. Move the pointer onto the disabled item.

Expected behavior

The flyout closes, same as hovering any other non-flyout item.

Is this issue blocking you?

No, however there is no workaround without avoiding hard-disabled items.

What is your environment?

• OS: macOS

• Browser: Chrome

• Version: PatternFly React 6.6.0

What is your product and what release date are you targeting?

OpenShift Virtualization (kubevirt-plugin)

Any other information?

Seen in MenuItem.js: onMouseOver on the li is a no-op when isAriaDisabled is true. CSS: pointer-events: none on disabled list items.

https://github.com/user-attachments/assets/2b2aa70e-57ad-4ec5-97c2-2ccb8148bc8f

Jira Issue: PF-4613

从 MenuItem.js 开始，重点关注 issue 中描述的 disabled 和 aria-disabled 处理，并检查 disabled 项的 CSS 行为。使用其 trigger 之后的 disabled 项重现 flyout 交互，然后验证移动到任一 disabled 变体上时，flyout 会像对待非 flyout 项一样关闭。