module-editoruitoolkitcustomization/Editor/EditorUIToolkitCustomization.cs

using UnityEditor;
using UnityEngine;
using UnityEngine.UIElements;

namespace Module.UIToolkit.Editor
{
    internal static class EditorUIToolkitCustomization
    {
        private static StyleSheet _ussCollectionView;
            
        [InitializeOnLoadMethod]
        private static void Initialize()
        {
            EditorApplication.update -= EditorTick;
            EditorApplication.update += EditorTick;
        }

        private static void EditorTick()
        {
            ApplyChanges();
        }

        private static void InitializeStyleSheets()
        {
            if (_ussCollectionView == null)
                _ussCollectionView = FindStyleSheet("editor-collection-view");
        }

        internal static void ApplyChanges()
        {
            InitializeStyleSheets();
            
            var settings = Settings.Load();
            var windows = GetAllOpenEditorWindows();
            
            for (var i = 0; i < windows.Length; i++)
            {
                var window = windows[i];
                var ve = window.rootVisualElement;

                if (ve == null)
                    continue;

                if (_ussCollectionView != null)
                {
                    if (settings.listViewDisableMaxHeight)
                        ve.styleSheets.Add(_ussCollectionView);
                    else
                        ve.styleSheets.Remove(_ussCollectionView);
                }
            }
        }

        private static StyleSheet FindStyleSheet(string name)
        {
            var guids = AssetDatabase.FindAssets($"t:{nameof(StyleSheet)} {name}");

            if (guids.Length == 0)
                return null;

            var path = AssetDatabase.GUIDToAssetPath(guids[0]);
            return AssetDatabase.LoadAssetAtPath<StyleSheet>(path);
        }

        private static EditorWindow[] GetAllOpenEditorWindows()
        {
            return Resources.FindObjectsOfTypeAll<EditorWindow>();
        }
    }
}