mat-menu nested with open and close with mouseenter and mouseleave

[dongjin son]

I want to make mat-menu to open and close dropdown menu without button click. 

I can fined the following sample code

https://stackblitz.com/edit/mat-nested-menu-yclrmd?embed=1&file=app/nested-menu-example.html

, but when I tried to use it from angular 17 (angular-material 17), I see the following exception

ERROR TypeError: Cannot read properties of undefined (reading '_elementRef')

from 

this.ren.removeClass(

trigger.menu.items.first['_elementRef'].nativeElement,

'cdk-focused'

);

I'm new to Angular, and can someone know what can be the cause of this issue?

Thank you!