Details
Description
When creating a Tag the "parent" field is not set as required, but omitting it leads to database errors.
Steps to reproduce:
1. Login as admin
2. Go to Content Structure
3. Start creating a new Tag
4. Fill the Tag Name and identifier - do not fill the "Parent" field
5. Click "Save"
Expected:
It's not possible to create a Tag without specyfing a parent
Actual:
Exception:
An exception has been thrown during the rendering of a template ("More than one result was found for query although one row or none was expected.").