Unity Context Menu Editor Window

ContextMenuEditor.cs

using System.Collections.Generic;
using UnityEngine;
using UnityEditor;
using System.Reflection;
public class ContextMenuEditor : EditorWindow
{
    [MenuItem("Tools/Edit Context Menu")] static void Init() => GetWindow<ContextMenuEditor>().Show();

    System.Type UnityEditorMenuClass;
    void GetMenuItemDefaultShortcuts(List<string> outItemNames, List<string> outItemDefaultShortcuts)
        => UnityEditorMenuClass?.GetMethod("GetMenuItemDefaultShortcuts", BindingFlags.Static | BindingFlags.NonPublic)
            .Invoke(null, new object[] { outItemNames, outItemDefaultShortcuts });
    void RemoveMenuItem(string name)
        => UnityEditorMenuClass?.GetMethod("RemoveMenuItem", BindingFlags.Static | BindingFlags.NonPublic)
            .Invoke(null, new object[] { name });

    class Node 
    { 
        public bool open = false;
        public bool delete = false;
        public string name; 
        public string path;
        public Node parent;
        public List<Node> children; 
    }

    List<string> menuItemNames;
    List<string> menuItemDefaultShortcuts;

    private void OnEnable()
    {
        UnityEditorMenuClass = null;
        System.Type[] assemblyTypes = Assembly.GetAssembly(typeof(Editor)).GetTypes();
        foreach( var t in assemblyTypes ) if( t.Namespace == "UnityEditor" && t.Name == "Menu" ) UnityEditorMenuClass = t;

        if (UnityEditorMenuClass == null) { broken = true; return; }

        FetchMenu();
    }

    void FetchMenu()
    {
        menuItemNames = new List<string>();
        menuItemDefaultShortcuts = new List<string>();

        GetMenuItemDefaultShortcuts(menuItemNames, menuItemDefaultShortcuts);

        root = new Node { children = new List<Node>() };

        foreach (var path in menuItemNames)
        {
            var node = root;
            var items = path.Split('/');

            foreach (var item in items)
            {
                var found = false;

                foreach (var n in node.children)
                {
                    if (n.name == item)
                    {
                        found = true;
                        node = n;
                        break;
                    }
                }

                if (!found)
                {
                    var n = new Node
                    {
                        children = new List<Node>(),
                        parent = node,
                        name = item,
                        path = path
                    };

                    node.children.Add(n);
                    node = n;
                }
            }
        }
    }


    bool broken = false;
    Node root;
    Vector2 scroll;

    void OnGUI()
    {
        if( broken ) { GUILayout.Label("This is broken, fix me !", EditorStyles.boldLabel); return; }

        using( var scope = new GUILayout.ScrollViewScope( scroll ) )
        {
            GUILayout.Space(20);

            GUILayout.Label( "Context Menu Tree: " , EditorStyles.boldLabel );

            foreach (var node in root.children) DrawNode( node );

            scroll = scope.scrollPosition;
        }

        GUILayout.Space( 10 );

        if( GUILayout.Button( "Delete Selected" ) )
        {
            EachNode( n => 
            { 
                if( n.delete ) RemoveMenuItem( n.path );
            } );
        }
    }

    void DrawNode( Node node, int intend = 0 )
    {
        using (new GUILayout.HorizontalScope())
        {
            GUILayout.Space( intend * 20 );

            var content = new GUIContent( node.name, node.path );

            if( node.children != null && node.children.Count > 0 )
            {
                node.open = EditorGUILayout.Foldout( node.open, content );
            }
            else GUILayout.Label( content );

            GUILayout.FlexibleSpace();

            node.delete = GUILayout.Toggle( node.delete, GUIContent.none );
        }

        if( node.open )
        {
            if( node.children != null && node.children.Count > 0 )
            {
                foreach (var child in node.children)
                {
                    DrawNode( child , intend + 1 );
                }
            }
        }

    }
    void EachNode(System.Action<Node> callback, Node node = null)
    {
        if (node == null) node = root;

        foreach (var n in node.children)
        {
            EachNode(callback, n);

            callback(n);
        }
    }

}