Repro steps:
Using Adminmenu.cs, add a first level menuItem without adding the corresponding custom "NavigationItemText" shape template as done here.

The layout for the menuItem looks ugly:

This issue is not relevant if people add menu items through code only, because it is expected that the developer provides a custom template.
But with the content tree module is going to be easy to add root items through UI and we should provide some better default.

I prepared a PR to fix that. Here is a gif: