ToggleWindowLock

using System;
using System.Reflection;
using UnityEditor;

namespace Plugins.Gists.Editor
{
    public static class InspectorLockToggle
    {
        [MenuItem("Tools/Toggle Lock &q")]
        static void ToggleWindowLock() // Inspector must be inspecting something to be locked
        {
            EditorWindow windowToBeLocked = EditorWindow.mouseOverWindow; // "EditorWindow.focusedWindow" can be used instead
 
            if (windowToBeLocked != null  && windowToBeLocked.GetType().Name == "InspectorWindow")
            {
                Type type = Assembly.GetAssembly(typeof(UnityEditor.Editor)).GetType("UnityEditor.InspectorWindow");
                PropertyInfo propertyInfo = type.GetProperty("isLocked");
                bool value = (bool)propertyInfo.GetValue(windowToBeLocked, null);
                propertyInfo.SetValue(windowToBeLocked, !value, null);
                windowToBeLocked.Repaint();
            }
            else if (windowToBeLocked != null  && windowToBeLocked.GetType().Name == "ProjectBrowser")
            {
                Type type = Assembly.GetAssembly(typeof(UnityEditor.Editor)).GetType("UnityEditor.ProjectBrowser");
                PropertyInfo propertyInfo = type.GetProperty("isLocked", BindingFlags.NonPublic | BindingFlags.Public |BindingFlags.Instance);
                
                bool value = (bool)propertyInfo.GetValue(windowToBeLocked, null);
                propertyInfo.SetValue(windowToBeLocked, !value, null);
                windowToBeLocked.Repaint();
            }
            else if (windowToBeLocked != null  && windowToBeLocked.GetType().Name == "SceneHierarchyWindow")
            {
                Type type = Assembly.GetAssembly(typeof(UnityEditor.Editor)).GetType("UnityEditor.SceneHierarchyWindow");
                
                FieldInfo fieldInfo = type.GetField("m_SceneHierarchy", BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance);
                PropertyInfo propertyInfo = fieldInfo.FieldType.GetProperty("isLocked",
                    BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance);
                object value = fieldInfo.GetValue(windowToBeLocked);
                bool value2 = (bool)propertyInfo.GetValue(value);
                propertyInfo.SetValue(value, !value2, null);
                windowToBeLocked.Repaint();
            }
        }
    }
}

Alt + Q

Brilliant! Still works in 2019.4.15

This is one of those things that is so useful that is blows my mind its a custom script. THANK YOU FOR MAKING IT AVAILABLE!!!!!