Have multi-level menus been implemented yet?

[ghost]

Is your feature request related to a problem?

When I click on a menu item, I want to load a submenu and so on.

Describe the solution you'd like:

Something like this

Describe alternatives you've considered:

Right now, I just create a new PowerMenu at the same location as the previous one with the desired submenu. However, it feels awkward and I wouldn't call it a true solution (since I am creating an entirely different PowerMenu instead of just creating a submenu in the old one and besides the submenu described by @skydoves in the link I posted looks way better)