CustomEntityEditor.cs

using System.Linq;
using System.Reflection;
using UnityEditor;
using UnityEditor.ShortcutManagement;
using UnityEngine;
using UnityEngine.UIElements;

namespace Junk.Entities.Editor
{
    [InitializeOnLoad]
    public static partial class CustomEntityEditor
    {
        private static UnityEditor.Editor m_EntityEditor;

        static CustomEntityEditor()
        {
            // Hook into the Editor lifecycle when the inspector is created
            UnityEditor.Editor.finishedDefaultHeaderGUI += OnFinishedDefaultHeaderGUI;
            EditorApplication.update                    += InitializeFrameShortcut;
        }
        
        // Add these new members to your class
        private static bool           m_IsSubscribedToSceneView;
        private static KeyCode        m_FrameKey       = KeyCode.F;
        private static EventModifiers m_FrameModifiers = EventModifiers.None;
        
        private static void InitializeFrameShortcut()
        {
            if (!m_IsSubscribedToSceneView)
            {
                SceneView.duringSceneGui  += DuringSceneGui;
                m_IsSubscribedToSceneView =  true;
            }
        }

        private static void DuringSceneGui(SceneView sceneView)
        {
            KeyDown(Event.current);
        }
        
        private static void KeyDown(Event evt)
        {
            // if this check isnt here, any clicked entity will frame automatically. could be useful but would need a checkbox
            if (evt.keyCode != KeyCode.F) 
                return;
            
            var combination = ShortcutManager.instance.GetShortcutBinding("Main Menu/Edit/Frame Selected in Window under Cursor")
                .keyCombinationSequence.ToList();
            
            if (combination.Count == 1)
            {
                EditorComponentManager.FrameSelectedEntity(m_EntityEditor);
                // Prevent default framing behavior
                //Event.current.Use();
            }
        }
        // Add this to your cleanup if you implement proper disposal
        // [InitializeOnLoad] classes should generally remain subscribed though
        private static void OnDestroy()
        {
            SceneView.duringSceneGui -= DuringSceneGui;
            EditorApplication.update -= InitializeFrameShortcut;
        }
        
        
        
        
        private static void OnFinishedDefaultHeaderGUI(UnityEditor.Editor editor)
        {
            m_EntityEditor = editor;
            // Check if the target editor is an EntityEditor
            if (editor.GetType().Name != "EntityEditor") 
                return;
            
            // Try to retrieve the root visual element
            var root = GetRootVisualElement(editor);
            
            // Check if the container already exists
            if (root.Q<VisualElement>("JunkEntityInspectorHeaderContainer") == null)
            {
                var container = new VisualElement
                {
                    name = "JunkEntityInspectorHeaderContainer",
                    style =
                    {
                        flexDirection = FlexDirection.Row,
                        marginBottom  = 5,
                        marginLeft    = 5,
                        marginRight   = 5,
                        paddingLeft   = 0,
                        paddingRight  = 0
                    }
                };

                // Schedule the addition of the container
                root.schedule.Execute(() =>
                {
                    // Double-check if the container still doesn't exist
                    if (root.Q<VisualElement>("JunkEntityInspectorHeaderContainer") == null)
                    {
                        root.Insert(0, container);
                    }
                });
                
                TryAddFoldoutElements(root, container, 0);
                TryAddDeleteElements(root, container, 1);
            }

        }
        
        internal static VisualElement GetRootVisualElement(UnityEditor.Editor editor)
        {
            // Access the private `m_Root` field from the EntityEditor
            var rootField = editor.GetType().GetField("m_Root", BindingFlags.NonPublic | BindingFlags.Instance);
            return rootField?.GetValue(editor) as VisualElement;
        }
    }
}

EditorComponentManager.cs

using System.Linq;
using Unity;
using Unity.Entities;
using Unity.Mathematics;
using Unity.Transforms;
using UnityEditor;
using UnityEngine.UIElements;

namespace Junk.Entities.Editor
{
    internal static class EditorComponentManager
    {
        public static void FrameSelectedEntity(UnityEditor.Editor entityEditor)
        {
            if (entityEditor == null)
                return;
            
            var root          = CustomEntityEditor.GetRootVisualElement(entityEditor);

            var componentsTab = root?.Query<VisualElement>("ComponentsTab").First();
            if (componentsTab == null)
                return;

            var localTransformData = LocalTransform.Identity;
            var isLocalToWorld     = false;
            var localToWorldData   = new LocalToWorld();
            
            var localTransform   = componentsTab.Query("LocalTransform").First();
            if (localTransform != null)
            {
                //Debug.Log("Framing selected entity");
                var vector3 = localTransform.Query("Position").First();
                var data    = vector3 as Vector3Field;
                localTransformData.Position = data.value;
            }
            var localToWorld = componentsTab.Query("LocalToWorld").First();
            
            var haveTransform = localTransform != null || localToWorld != null;
            
            
            if (localToWorld != null)
            {
                //Debug.Log("Found localToWorld" + localToWorld.GetType());
                
                // get all children of localToWorld
                var children = localToWorld.Children();
                //var child = localToWorld.ElementAt(1).ElementAt(1).ElementAt(1).ElementAt(1);
                //Unity.Debug.Log(children.Count());
                // get child
                var first  = children.First();
                var second = first.Children().First(); // bindableelement
                
                // Get all Vector4Fields 
                var floatFields = second.Children().ToList().Select(x => x.Q<Vector4Field>()).ToList();
                //Debug.Log("Found " + floatFields.Count + " Vector4Fields");
                    
                //Debug.Log($"floatFields {floatFields.Count}");
                    
                localToWorldData = new LocalToWorld{Value = new float4x4
                {
                    c0 = floatFields[0].value,
                    c1 = floatFields[1].value,
                    c2 = floatFields[2].value,
                    c3 = floatFields[3].value
                }};
                //Debug.Log($"localToWorld {localToWorldData.Position}");
                isLocalToWorld = true;
            }
            
            if (haveTransform)
            {
                var position = localTransformData.Position;
                
                //if (position.Equals(Vector3.zero))
                {
                    if (localToWorld != null)
                    {
                        //Debug.Log($" localToWorldData {localToWorldData.Position}");
                        position = localToWorldData.Position;
                    }
                }
                    
                // get scene view camera
                var sceneView = SceneView.lastActiveSceneView;
                if (sceneView != null)
                {
                    //Frame selected in scene view
                    sceneView.pivot = position;
                        
                    sceneView.Repaint();
                }
            }
        }

        public static void DeleteEntity(VisualElement root, bool b)
        {
            var entityNameField   = root.Q<TextField>("Entity Name");
            var child             = entityNameField.Children().First();
            var textElement       = child.Children().First();
            var entityTextElement = textElement as TextElement;
            var entityNameText    = entityNameField.text;
            // name is parsed as: Entity {105:1}, we are only interested in the index and version of the entity which is {index:version}
            Entity entity = new Entity {Index = int.Parse(entityNameText.Split('{')[1].Split(':')[0]), Version = int.Parse(entityNameText.Split(':')[1].Split('}')[0])};
            
            var entityManager = World.DefaultGameObjectInjectionWorld.EntityManager;
            if (entityManager.Exists(entity))
            {
                entityManager.DestroyEntity(entity);
            }
            Debug.Log($"Deleted entity: {entityNameText}, {entity.Index } {entity.Version}");

            Selection.activeObject = null;
        }
    }
}

EntityEditorCollapseFoldout.cs

using Unity.Entities.Editor;
using UnityEngine;
using UnityEngine.UIElements;

namespace Junk.Entities.Editor
{
    public static partial class CustomEntityEditor
    {
        private static void TryAddFoldoutElements(VisualElement root, VisualElement containerElement, int index)
        {
            if (containerElement != null && !IsCollapseButtonAdded(containerElement))
            {
                AddFoldoutButtons(root, containerElement, index);
            }
        }

        private static bool IsCollapseButtonAdded(VisualElement containerElement)
        {
            // Check if the button already exists to prevent duplication
            return containerElement.Q<Button>("CollapseExpandContainer") != null;
        }


        private static void AddFoldoutButtons(VisualElement root, VisualElement containerElement, int index)
        {
            // Schedule the button addition to prevent hierarchy modification during layout calculation
            containerElement.schedule.Execute(() =>
            {
                if (!IsCollapseButtonAdded(containerElement))
                {
                    var subContainer = new VisualElement
                    {
                        name = "CollapseExpandContainer",
                        
                        style =
                        {
                            //position = Position.Absolute,
                            //top      = 0,
                            //right    = 0,
                            paddingTop    = 0,
                            paddingBottom = 0,
                            paddingLeft   = 0,
                            paddingRight  = 0,
                            flexDirection = FlexDirection.Row,
                        }
                    };
                    var expand = new Button(() => { ExpandComponentsTabFoldout(root, true); })
                    {
                        name    = "Expand",
                        text    = "Expand",
                        tooltip = "Expand all components",
                        style =
                        {
                            paddingTop              = 4,
                            paddingBottom           = 4,
                            paddingLeft             = 8,
                            paddingRight            = 8,
                            backgroundColor         = new Color(0.35f, 0.35f, 0.35f, 0.8f), // Modern green
                            color                   = Color.white,
                            borderTopLeftRadius     = 0,
                            borderTopRightRadius    = 0,
                            borderBottomLeftRadius  = 6,
                            borderBottomRightRadius = 6,
                            whiteSpace              = WhiteSpace.NoWrap,
                            width                   = Length.Auto(),
                            flexShrink              = 0,
                            marginLeft              = 0,
                            marginRight             = 0
                        }
                    };

                    var collapse = new Button(() => { ExpandComponentsTabFoldout(root, false); })
                    {
                        name    = "Collapse",
                        text    = "Collapse",
                        tooltip = "Collapse all components",
                        style =
                        {
                            paddingTop              = 4,
                            paddingBottom           = 4,
                            paddingLeft             = 8,
                            paddingRight            = 8,
                            backgroundColor         = new Color(0.35f, 0.35f, 0.35f, 0.8f),
                            color                   = Color.white,
                            borderTopLeftRadius     = 0,
                            borderTopRightRadius    = 0,
                            borderBottomLeftRadius  = 6,
                            borderBottomRightRadius = 6,
                            whiteSpace              = WhiteSpace.NoWrap,
                            width                   = Length.Auto(),
                            flexShrink              = 0,
                            marginLeft              = 0,
                            marginRight             = 0
                        }
                    };

                    // Add hover effects
                    expand.RegisterCallback<MouseEnterEvent>(_ => expand.style.backgroundColor = new Color(0.20f, 0.72f, 0.42f));
                    expand.RegisterCallback<MouseLeaveEvent>(_ => expand.style.backgroundColor = new Color(0.35f, 0.35f, 0.35f, 0.8f));

                    collapse.RegisterCallback<MouseEnterEvent>(_ => collapse.style.backgroundColor = new Color(0.96f, 0.41f, 0.37f));
                    collapse.RegisterCallback<MouseLeaveEvent>(_ => collapse.style.backgroundColor = new Color(0.35f, 0.35f, 0.35f, 0.8f));

                    subContainer.Add(expand);
                    subContainer.Add(collapse);
                    containerElement.Insert(index, subContainer);
                    
                }
            });
        }
        
        private static void ExpandComponentsTabFoldout(VisualElement root, bool value)
        {
            var componentsTab = root.Query<VisualElement>("ComponentsTab").First();

            if (componentsTab != null)
            {
                // get all children and log their count
                var allComponentsTabs = root.Query<ComponentElementBase>().ToList();

                foreach (var component in allComponentsTabs)
                {
                    var foldout = component.Query<Foldout>().First(); // Assumes one foldout per component
                    if (foldout != null)
                    {
                        foldout.value = value;
                    }
                }
            }
        }
    }
}

EntityEditorDeleteEntity.cs

using Unity.Entities.Editor;
using UnityEngine;
using UnityEngine.UIElements;

namespace Junk.Entities.Editor
{
    public static partial class CustomEntityEditor
    {
        private static void TryAddDeleteElements(VisualElement root, VisualElement container, int index)
        {
            if (container != null && !IsDeleteButtonAdded(container))
            {
                AddDeleteButtons(root, container, index);
            }
        }
        
        private static bool IsDeleteButtonAdded(VisualElement container)
        {
            // Check if the button already exists to prevent duplication
            return container.Q<Button>("DeleteEntity") != null;
        }
        
        private static void AddDeleteButtons(VisualElement root, VisualElement container, int index)
        {
            // Schedule the button addition to prevent hierarchy modification during layout calculation
            container.schedule.Execute(() =>
            {
                if (!IsDeleteButtonAdded(container))
                {
                    var buttonContainer = new VisualElement
                    {
                        style =
                        {
                            flexDirection = FlexDirection.Row,
                            marginBottom = 0,
                            marginLeft   = 0,
                            marginRight  = 0,
                            paddingLeft  = 0,
                            paddingRight = 0
                        }
                    };

                    var deleteEntityButton = new Button(() => { EditorComponentManager.DeleteEntity(root, false); })
                    {
                        name    = "DeleteEntity",
                        text    = "Delete Entity",
                        tooltip = "Destroy the entity",
                        style =
                        {
                            paddingTop              = 4,
                            paddingBottom           = 4,
                            paddingLeft             = 8,
                            paddingRight            = 8,
                            backgroundColor         = new Color(0.35f, 0.35f, 0.35f, 0.8f),
                            color                   = Color.white,
                            borderTopLeftRadius     = 0,
                            borderTopRightRadius    = 0,
                            borderBottomLeftRadius  = 6,
                            borderBottomRightRadius = 6,
                            whiteSpace              = WhiteSpace.NoWrap,
                            width                   = Length.Auto(),
                            flexShrink              = 0,
                            marginLeft              = 0,
                            marginRight             = 0
                        }
                    };

                    // Add hover effects
                    deleteEntityButton.RegisterCallback<MouseEnterEvent>(_ => deleteEntityButton.style.backgroundColor = new Color(0.96f, 0.41f, 0.37f));
                    deleteEntityButton.RegisterCallback<MouseLeaveEvent>(_ => deleteEntityButton.style.backgroundColor = new Color(0.35f, 0.35f, 0.35f, 0.8f));

                    buttonContainer.Add(deleteEntityButton);
                    container.Insert(index, buttonContainer);
                }
            });
        }
    }
}