Edit property dialog doesn't persist type (when using Long or Boolean)

It's not possible edit properties with another type than String using the dialog, because the site configuration admin UI does not allow to change a property node type to Boolean or Long, it always remains String, even after editing it.

Property dialog - changing type to Boolean:

But it remains a String:

Workaround

Instead of using the dialog, double-click on the column and edit the value there.