Inspector not displaying an array of arrays

I implemented something like this about 3 months ago in another project, it was in 5.5.0 and worked fine:

[SerializeField]
public class PictureFragments
{
	public GameObject fragment1;
	public GameObject fragment2;
	public GameObject fragment3;
}
public PictureFragments[] pictureFragments;

But using 5.5.1 and the array does not want to display in the inspector (the console is not displaying any errors either). Has this function been removed in the most recent version or is it not implemented correctly?

You need to use System.Serializable on the PictureFragments class, not SerializeField

You may be better off using ScriptableObjects

using UnityEngine;

//Class / Script that is added to a GameObject
public class InspectorClass : MonoBehaviour {
    public PictureFragments[] pictureFragments;
}

//This allows you to create a asset in your project by Right Clicking / Create / PictureFragments
//Then assign the PictureFragments Scriptable object into the array on the GameObject
[CreateAssetMenu(menuName = "PictureFragments")]
public class PictureFragments : ScriptableObject
{
    public GameObject fragment1;
    public GameObject fragment2;
    public GameObject fragment3;
}