CustomDebugWIndow is an editor script that provides a way to inspect data, objects, and states over time

CustomDebugWindow.cs

using UnityEngine;
#if UNITY_EDITOR
using UnityEditor;
#endif
using System.Collections;
using System.Collections.Generic;
using System;


// to get this to work, this class musc exist outside "Editor" folder 
// otherwise non-editor classes cannot access this
// therefore, tons of #ifdef T_T

public class CustomDebugWindow
#if UNITY_EDITOR
    : EditorWindow
#endif
{
    static Dictionary<object, LayoutHelper> debugUIList = new Dictionary<object, LayoutHelper>();

#if UNITY_EDITOR
    static void GetWindow()
    {
        EditorWindow.GetWindow<CustomDebugWindow>().Show();
    }

    void Update()
    {
        // force editor window to redraw even when not focused
        // otherwise editor window does not refresh action() data until focus
        Repaint();
    }


	static GUIStyle style = new GUIStyle();
    Vector2 scrollPos = Vector2.zero;
    public static int widthPerPanel = 300;
    void OnGUI()
    {
        if (!Application.isPlaying && debugUIList.Keys.Count > 0) debugUIList = new Dictionary<object, LayoutHelper>();
        GUI.skin.label.wordWrap = true;
        GUI.skin.button.wordWrap = true;
        GUI.color = Color.white;
        
        widthPerPanel = EditorGUILayout.IntField("width per panel", widthPerPanel);
        scrollPos = GUILayout.BeginScrollView(scrollPos, false, false);
        int idx = 0;

        foreach (var kvp in debugUIList)
        {
			style.active.background = CreateBackGround(1, 1, Color.white);
            GUILayout.BeginArea(kvp.Value.rect, style);
            GUILayout.Space(20);
            //kvp.Value.extraWidth = EditorGUILayout.IntField("extra width for this panel", kvp.Value.extraWidth);

            GUI.backgroundColor = Color.magenta;
            if(GUILayout.Button("select caling object: " + kvp.Key.GetType()))
            {
                EditorGUIUtility.PingObject(kvp.Key as UnityEngine.Object);
            }

            GUI.backgroundColor = Color.cyan;
            // reset colors in case called actions have color coding
            GUI.color = Color.white;

            kvp.Value.width = widthPerPanel ;
            kvp.Value.x = widthPerPanel * idx;
            idx++;

            kvp.Value.scrollPos = GUILayout.BeginScrollView(kvp.Value.scrollPos, false, true);

            if (kvp.Key == null)
            {
                GUILayout.Label("context was null: make sure to remove objects on destroy");
                GUILayout.EndScrollView();
                GUILayout.EndArea();
                continue;
            }

            if (kvp.Value == null)
            {
                GUI.color = Color.red;
                GUILayout.Label("layout helper became null");
                GUILayout.EndScrollView();
                GUILayout.EndArea();
                continue;
            }

			if(kvp.Value.actions != null)
			foreach (var action in kvp.Value.actions)
			{
				Color c = GUI.backgroundColor;
				GUI.backgroundColor = Color.red;
				if (GUILayout.Button("remove from list"))
				{
					kvp.Value.removeThisAction = action;
				}
				GUI.backgroundColor = c;
				GUILayout.Label(action(), GUILayout.Width(widthPerPanel));
			}

			GUI.backgroundColor = Color.cyan;
			GUILayout.Button("formatted actions: ", EditorStyles.toolbarButton);
			GUI.backgroundColor = Color.white;

			if(kvp.Value.formattedActions != null)
			foreach (var action in kvp.Value.formattedActions)
			{
				Color c = GUI.backgroundColor;
				GUI.backgroundColor = Color.red;
				if (GUILayout.Button("remove from list"))
				{
					kvp.Value.removeThisFormattedAction = action;
				}
				GUI.backgroundColor = c;
				action();
			}


			kvp.Value.RemoveAction();
			kvp.Value.RemoveFormattedAction();

            GUI.backgroundColor = Color.grey;
            GUILayout.EndScrollView();
            GUILayout.EndArea();

        }
        GUILayout.EndScrollView();
    }
#endif

    static public void Add(Func<string> act, object context)
    {
#if UNITY_EDITOR
		if (!debugUIList.ContainsKey(context) || debugUIList[context] == null)
		{
			debugUIList[context] = new LayoutHelper();
		}

		if(debugUIList[context].actions == null)			debugUIList[context].actions = new List<Func<string>>();
        if (!debugUIList[context].actions.Contains(act))	debugUIList[context].actions.Add(act);
        
        SetRects(context);
        GetWindow();
#endif
    }

	static public void AddFormattedAction(Action act, object context)
	{
		if (!debugUIList.ContainsKey(context) || debugUIList[context] == null)
		{
			debugUIList[context] = new LayoutHelper();
		}

		if(debugUIList[context].formattedActions == null)			debugUIList[context].formattedActions = new List<Action>();
		if (!debugUIList[context].formattedActions.Contains(act))	debugUIList[context].formattedActions.Add(act);

		SetRects(context);
		GetWindow();
	}

    static public void Remove(object context)
    {
#if UNITY_EDITOR
        debugUIList.Remove(context);
#endif
    }

    static void SetRects(object context)
    {
#if UNITY_EDITOR

        Rect window = new Rect();
        window.width = Screen.width;
        window.height = Screen.height;
        window.position = Vector2.zero;
		
        int i = 0;
        foreach (var kvp in debugUIList)
        {
            kvp.Value.position = new Vector2(window.position.x + (i * widthPerPanel), window.position.y);
            kvp.Value.size = new Vector2(widthPerPanel, window.size.y);
            i++;
        }

#endif
    }

	static Texture2D CreateBackGround(int width, int height, Color col)
	{
		Color[] pix = new Color[width * height];

		for (int i = 0; i < pix.Length; i++)
			pix[i] = col;

		Texture2D result = new Texture2D(width, height);
		result.SetPixels(pix);
		result.Apply();

		return result;
	}




    class LayoutHelper
    {
        public Rect rect;
        public float width { get { return size.x; } set { size = new Vector2(value + extraWidth, size.y); } }
        public float x {  get { return position.x; } set { position = new Vector2(value, position.y); } }
        public int extraWidth { get; set; }
        
        public Vector2 size { get { return rect.size; } set { rect.size = value; } }
        public Vector2 position { get { return rect.position; } set { rect.position = value; } }
        public Vector2 scrollPos = Vector2.zero;
        public List<Func<string>> actions;

		public List<Action> formattedActions;

        public Func<string> removeThisAction;
		public Action removeThisFormattedAction;

        public void RemoveAction()
        {
            if(removeThisAction != null && actions.Contains(removeThisAction))
            {
                actions.Remove(removeThisAction);
                removeThisAction = null;
            }
        }

		public void RemoveFormattedAction()
		{
			if (removeThisFormattedAction != null && formattedActions.Contains(removeThisFormattedAction))
			{
				formattedActions.Remove(removeThisFormattedAction);
				removeThisFormattedAction = null;
			}
		}
    }

}