[SOLVED] How to use multiple object fields in custom editor?

I am creating a custom window with multiple object fields. Whatever I do I can only get 1 field to work and accept TextAssets. The XmlFile attribute works, the other two don't.

They look exactly the same to me and I really can't tell what I'm doing wrong. It could be something very simple as I am very new to Unity.

Any help is much appreciated!

UPDATE

I was assigning to Font instead of FontMetadata in the third call to .ObjectField(). Assigning to the proper field fixed the issue completely.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEditor;
 using UnityEngine;
 
 public class CustomWindow : EditorWindow
 {
     public TextAsset Font;
 
     public TextAsset XmlFile;
 
     public TextAsset FontMetadata;
 
     [MenuItem("Window/XML")]
     public static void ShowWindow()
     {
         var window = EditorWindow.GetWindow(typeof(CustomWindow), false, "Custom import");
         //window.Show();
     }
 
     public void OnGUI()
     {
         GUILayout.Label("Import settings", EditorStyles.boldLabel);
         EditorGUIUtility.labelWidth = 100;
         this.Font = (TextAsset)EditorGUILayout.ObjectField("Font", this.Font, typeof(TextAsset), true);
         this.XmlFile = (TextAsset)EditorGUILayout.ObjectField("XML file", this.XmlFile, typeof(TextAsset), true);
         this.Font = (TextAsset)EditorGUILayout.ObjectField("Font metadata", this.FontMetadata, typeof(TextAsset), true);
 
         EditorGUILayout.BeginHorizontal();
         GUILayout.Space(100);
         bool clicked = GUILayout.Button("Process");
         EditorGUILayout.EndHorizontal();
         if (clicked)
         {
             Debug.Log("Should be processing now");
         }
     }
 }