Error when trying to add space element to navigation

Problem

The problem is that the app produces an error, saying that all required fields must be filled when leaving the alternative title blank. The moment you enter an alternative title, the app renames the original title to the alternative one, but it still keeps complaining that all required fields must be filled.

Solution

When you enter the key of a Confluence space in the SubSpace Navigation, you've got to make sure to click on the space when it's offered via autocomplete/in the dropdown, even when the key you entered in the field is written exactly the same. This helps to avoid the error message.