FORT-BO/Assets/CONTENT/FEATURES/MapRadar/Editor/MapTargetControllerEditor.cs

using UnityEditor;
using UnityEngine;

[CustomEditor(typeof(MapTargetController))]
public sealed class MapTargetControllerEditor : Editor
{
    public override void OnInspectorGUI()
    {
        DrawDefaultInspector();
        EditorGUILayout.Space();

        using (new EditorGUI.DisabledScope(!Application.isPlaying))
        {
            if (GUILayout.Button("Start Next Wave"))
                ((MapTargetController)target).StartNextWave();
        }

        if (!Application.isPlaying)
        {
            EditorGUILayout.HelpBox(
                "Start Next Wave becomes available in Play Mode.",
                MessageType.Info);
        }
    }
}