Allowed schemas in a node list field can't be changed after saving

[DevNils]

Gentics Mesh Version, operating system, or hardware.

• v1.3.2

Operating System

• MacOSX

JVM

• Oracle JDK 1.8.0_202

Problem

After saving them once, allowed schemas in a node list field can not be changed anymore in the UI.

Reproducer

• Start a fresh instance of mesh: MESH_INITIAL_ADMIN_PASSWORD_FORCE_RESET=0MESH_INITIAL_ADMIN_PASSWORD=admin java -jar mesh-server-1.3.2.jar
• Go to the admin area and create a new Schema named "test"
• Add a field named "test_field" of the type "list", the list type "node" and add the "Allowed Schema" "binary_content"
• Save it
• Try to remove or add "Allowed Schemas", it won't work
• Switch to the "JSON" tab, try to add or remove elements in "allow". If you save it and reload the page, your changes will not appear.

Expected behaviour and actual behaviour

The "Allowed Schemas" should be changeable after saving them once.