Scriptable Object With Paging

// ------- MyStringScriptableObject .cs
using System.Collections.Generic;
using UnityEngine;

[CreateAssetMenu ( fileName = "MyStringScriptableObject", menuName = "New Scriptable Object/MyStringScriptableObject", order = 1 )]
public class MyStringScriptableObject : ScriptableObject
{
    public List<string> myStrings;
    public MyStringScriptableObject ( )
    {
        myStrings = new List<string> ( );
    }
}



// ------- ListEditor .cs
using System.Collections.Generic;
using UnityEditor;
using UnityEngine;

[CustomEditor ( typeof ( MyStringScriptableObject ) )]
public class ListEditor : Editor
{
    int currentIndex = 0;
    int lastIndex = 0;
    int pageSize = 3;
    bool updateList = true;

    public override void OnInspectorGUI ( )
    {
        MyStringScriptableObject myStrings = ( MyStringScriptableObject ) target;
        if ( myStrings == null ) return;

        // --------------------------------------------------------------------------------- Default Map
        if ( currentIndex == 0 )
        {
            if ( myStrings.myStrings == null ) myStrings.myStrings = new List<string> ( 10 );
            if ( myStrings.myStrings.Count == 0 )
            {
                lastIndex = 10;
                for ( int i = 0; i < lastIndex; i++ )
                    myStrings.myStrings.Add ( $"New String at Index [{i}]..." );
            }
            lastIndex = Mathf.Clamp ( currentIndex + pageSize, 0, myStrings.myStrings.Count );
        }

        // --------------------------------------------------------------------------------- Previous And Next Buttons
        GUILayout.BeginHorizontal ( );
        if ( GUILayout.Button ( "< Prev", GUILayout.ExpandWidth ( false ) ) )
        {
            if ( currentIndex > 0 )
            {
                currentIndex = Mathf.Clamp ( currentIndex - pageSize, 0, myStrings.myStrings.Count );
                lastIndex = Mathf.Clamp ( currentIndex + pageSize, 0, myStrings.myStrings.Count );
            }
            updateList = true;
        }

        GUILayout.Space ( 5 );
        if ( GUILayout.Button ( "Next >", GUILayout.ExpandWidth ( false ) ) )
        {
            if ( currentIndex < ( myStrings.myStrings.Count - pageSize ) )
            {
                currentIndex = Mathf.Clamp ( currentIndex + pageSize, 0, myStrings.myStrings.Count );
                lastIndex = Mathf.Clamp ( currentIndex + pageSize, 0, myStrings.myStrings.Count );
                updateList = true;
            }
            updateList = true;
        }

        GUILayout.EndHorizontal ( );
        EditorGUIUtility.labelWidth = 200;
        currentIndex = EditorGUILayout.IntField ( "Current Index", currentIndex, GUILayout.ExpandWidth ( false ) );

        for ( int i = currentIndex; i < lastIndex; i++ )
        {
            EditorGUI.BeginChangeCheck ( );
            myStrings.myStrings [ i ] = EditorGUILayout.TextField ( $"Text[{i}]", myStrings.myStrings [ i ] );
            if ( EditorGUI.EndChangeCheck ( ) )
                EditorUtility.SetDirty( target );
        }

    }
}