Error message for empty menu item label is shown inside the field

The error message for an empty menu item label is shown inside the field instead of above it.

Steps to reproduce:
1. login to the archetype CMS
2. edit the only channel
3. edit the menu
4. empty the 'label' of the 'home' menu item

Expected: an error message is shown above the field
Actual: an error message is shown inside the field