**As** an OpenProject administrator
**I want to** interact with the custom fields administration 
**so that** I can create new custom fields of type hierarchy or edit existing ones.

**Acceptance criteria**

* On `/custom_fields/new?type=WorkPackageCustomField` the format dropdown contains the option "Hierarchy".

* When creating a custom field of type hierarchy we need to be able to set the following options:

* "Name" - Required, String

* "Allow multi-select" - Checkbox

* "Required" - Checkbox

* "For all projects" - Checkbox

* "Used as a filter" - Checkbox

* "Searchable" - Checkbox

* When the user clicks on "Save", the custom field details view is shown.

* ⚠️ the current behaviour redirect to custom fields index page. Can we change that for this custom field? Begin of the insertion-> No, not nowEnd of the insertion

* The custom field details view has two sub pages (tabs)

* Details

* The "Details" view shows the following options:

* "Name" - Required, String

* "Allow multi-select" - Checkbox

* "Required" - Checkbox

* "For all projects" - Checkbox

* "Used as a filter" - Checkbox

* "Searchable" - Checkbox

* Begin of the insertionItemsEnd of the insertion Begin of the deletion ValuesEnd of the deletion

* The Begin of the insertion"Items"End of the insertion Begin of the deletion "Values"End of the deletion view shows a placeholder for the empty Begin of the insertionitemsEnd of the insertion Begin of the deletion valuesEnd of the deletion after creation.

* The user must be able to create new Begin of the insertionitems.End of the insertion Begin of the deletion values.End of the deletion

* The user must be able to assign a label and a short to a new Begin of the insertionitem.End of the insertion Begin of the deletion value.End of the deletion

* The user is not allowed to create a Begin of the insertionitemEnd of the insertion Begin of the deletion valueEnd of the deletion with a label Begin of the insertion~~orEnd of the insertion Begin of the deletion orEnd of the deletion a Begin of the insertionshort~~End of the insertion Begin of the deletion shortEnd of the deletion that already exists on that level.

* The user must be able to submerge into a Begin of the insertionitemEnd of the insertion Begin of the deletion valueEnd of the deletion to create Begin of the insertionsub-items.End of the insertion Begin of the deletion child values.End of the deletion

* The user must be able to delete Begin of the insertionan item.End of the insertion Begin of the deletion a value.End of the deletion

* Deletion of a value deletes all Begin of the insertionsub-items.End of the insertion Begin of the deletion sub values.End of the deletion

* The user must be able to edit a Begin of the insertionitem.End of the insertion Begin of the deletion value.End of the deletion

* If the user submerged into any Begin of the insertionitem,End of the insertion Begin of the deletion value,End of the deletion a breadcrumb with the ancestors must be displayed. The user must be able to go to any of the current ancestors.


**Important hints**

* A deletion eventually is possible as hard or soft delete.

* The first iteration only supports hard delete.

* A soft delete marks a value and all descendants as deleted, but does not remove the entity from the database.

* A sorting is planned, hence the data model must support an order of values of the same level.