[PT Run] WindowWalker: Refactor code, fix some bugs, hide UWP non-windows, prepare code for new features (#15441)

* Import files from old PR #15329

* Improvements

* hide uwp non-windows (#13637)

* update debug tool tip

* fix spelling and comments

* disable tool tip

* fix doc links

* remove obsolete using

* Update docs

* fix spelling

* rename elevation property and test method

* Add property <DoesExist> to WindowProcess class

* Close process handles correctly if not used anymore

* cleanup coed

* fix bug with sticky notes process

* add window class to tool tip

* small change

* make nativeMethods static class

* fix broken uwpApp property of WindowProcess class

* rename method

* Revert making NativeMethods class static. It contains instance members.

* improve loggign

* fix merge mistakes

* fixes

* remove obsolete delegate

* Improve SearchController to speed up search (#15561)

* add <IsShellProcess> property to <WindowProcess> class

* reorder code

* disable debug tool tip

* Update devdocs

* remove obsolete event handler

* update var name

.github/actions/spell-check/expect.txt

@@ -723,6 +723,7 @@ HOLDESC
 homepage
 homljgmgpmcbpjbnjpfijnhipfkiclkd
 HOOKPROC
+Hostbackdropbrush
 hostname
 hotkeycontrol
 hotkeys

doc/devdocs/modules/launcher/plugins/windowwalker.md

@@ -3,16 +3,19 @@ The window walker plugin matches the user entered query with the open windows on
 
 ![Image of Window Walker plugin](/doc/images/launcher/plugins/windowwalker.png)
 
-### [`OpenWindows.cs`](src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/OpenWindows.cs)
-- The window walker plugin uses the `EnumWindows` function to enumerate all the open windows in the [`OpenWindows.cs`](src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/OpenWindows.cs) class.
+### [`OpenWindows.cs`](/src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/OpenWindows.cs)
+- The window walker plugin uses the `EnumWindows` function to enumerate all the open windows in the [`OpenWindows.cs`](/src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/OpenWindows.cs) class.
 
+### [`SearchController.cs`](/src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/SearchController.cs)
+- The [`SearchController`](/src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/SearchController.cs) encapsulates the functions needed to search and find matches.
+- It is responsible for updating the search text and performing a fuzzy search on all the open windows.
 
-### [`SearchController.cs`](src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/SearchController.cs)
-- The [`SearchController`](src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/SearchController.cs) encapsulates the functions needed to search and find matches.
-- It is responsible for updating the search text and performing a fuzzy search on all the open windows in an asynchronous manner.
+### [`Window.cs`](/src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/Window.cs)
+- The [`Window`](/src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/Window.cs) class represents a specific window and has functions to get the name of the window, the state of the window (whether it is visible or not), and the `SwitchTowindow` function which switches the desktop focus to the selected window. This action is performed when the user clicks on a window walker plugin result.
+- The `Window` class holds a static cache with the process information of all windows we know so far and each window instance has a property which holds its process information (name, file, ...). The process data in the cache and the window property are of the type `WindowProcess`.
 
-### [`Window.cs`](src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/Window.cs)
-- The [`Window`](src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/Window.cs) class represents a specific window and has functions to get the name of the process, the state of the window (whether it is visible or not), and the `SwitchTowindow` function which switches the desktop focus to the selected window. This action is performed when the user clicks on a window walker plugin result.
+### [`WindowProcess.cs`](/src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/WindowProcess.cs)
+- The [`WindowProcess`](/src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/WindowProcess.cs) class represents a specific process for a window. It contains static methods to query process information from the system. And it contains instance methods and properties to hold/retrieve the process information we want to know about a window's process.
 
 ### Score
-The window walker plugin uses [`FuzzyMatching`](src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/FuzzyMatching.cs) to get the matching indices and calculates the score by creating a 2 dimensional array of the window and the query text.
+The window walker plugin uses [`FuzzyMatching`](/src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/FuzzyMatching.cs) to get the matching indices and calculates the score by creating a 2 dimensional array of the window and the query text.

src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/NativeMethods.cs

@@ -249,7 +249,7 @@ namespace Microsoft.Plugin.WindowWalker.Components
         }
 
         /// <summary>
-        /// Window attribute
+        /// DWM window attribute (Windows 7 and earlier: The values between ExcludedFromPeek and Last aren't supported.)
         /// </summary>
         [Flags]
         public enum DwmWindowAttribute
@@ -266,9 +266,32 @@ namespace Microsoft.Plugin.WindowWalker.Components
             HasIconicBitmap,
             DisallowPeek,
             ExcludedFromPeek,
+            Cloak,
+            Cloaked,
+            FreezeRepresentation,
+            PassiveUpdateMode,
+            UseHostbackdropbrush,
+            UseImmersiveDarkMode,
+            WindowCornerPreference,
+            BorderColor,
+            CaptionColor,
+            TextColor,
+            VisibleFrameBorderThickness,
             Last,
         }
 
+        /// <summary>
+        /// Flags for describing the window cloak state (Windows 7 and earlier: This value is not supported.)
+        /// </summary>
+        [Flags]
+        public enum DwmWindowCloakState
+        {
+            None = 0,
+            CloakedApp = 1,
+            CloakedShell = 2,
+            CloakedInherited = 4,
+        }
+
         /// <summary>
         /// Flags for accessing the process in trying to get icon for the process
         /// </summary>
@@ -869,7 +892,7 @@ namespace Microsoft.Plugin.WindowWalker.Components
         [DllImport("user32.dll", SetLastError = true, BestFitMapping = false)]
         public static extern IntPtr GetProp(IntPtr hWnd, string lpString);
 
-        [DllImport("kernel32.dll")]
+        [DllImport("kernel32.dll", SetLastError = true)]
         public static extern IntPtr OpenProcess(ProcessAccessFlags dwDesiredAccess, [MarshalAs(UnmanagedType.Bool)] bool bInheritHandle, int dwProcessId);
 
         [DllImport("dwmapi.dll", EntryPoint = "#113", CallingConvention = CallingConvention.StdCall)]
@@ -890,5 +913,37 @@ namespace Microsoft.Plugin.WindowWalker.Components
 
         [DllImport("user32.dll")]
         public static extern int SendMessage(IntPtr hWnd, int msg, int wParam);
+
+        [DllImport("kernel32.dll")]
+        [return: MarshalAs(UnmanagedType.Bool)]
+        public static extern bool CloseHandle(IntPtr hObject);
+
+        [DllImport("user32.dll")]
+        public static extern IntPtr GetShellWindow();
+
+        /// <summary>
+        /// Returns the last Win32 Error code thrown by a native method if enabled for this method.
+        /// </summary>
+        /// <returns>The error code as int value.</returns>
+        public static int GetLastWin32Error()
+        {
+            return Marshal.GetLastWin32Error();
+        }
+
+        /// <summary>
+        /// Validate that the handle is not null and close it.
+        /// </summary>
+        /// <param name="handle">Handle to close.</param>
+        /// <returns>Zero if native method fails and nonzero if the native method succeeds.</returns>
+        public static bool CloseHandleIfNotNull(IntPtr handle)
+        {
+            if (handle == IntPtr.Zero)
+            {
+                // Return true if there is nothing to close.
+                return true;
+            }
+
+            return CloseHandle(handle);
+        }
     }
 }

src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/OpenWindows.cs

@@ -20,11 +20,6 @@ namespace Microsoft.Plugin.WindowWalker.Components
         /// </summary>
         private static readonly string _powerLauncherExe = Path.GetFileName(Process.GetCurrentProcess().MainModule.FileName);
 
-        /// <summary>
-        /// Delegate handler for open windows updates
-        /// </summary>
-        public delegate void OpenWindowsUpdateEventHandler(object sender, SearchController.SearchResultUpdateEventArgs e);
-
         /// <summary>
         /// List of all the open windows
         /// </summary>
@@ -93,9 +88,14 @@ namespace Microsoft.Plugin.WindowWalker.Components
 
             if (newWindow.IsWindow && newWindow.Visible && newWindow.IsOwner &&
                 (!newWindow.IsToolWindow || newWindow.IsAppWindow) && !newWindow.TaskListDeleted &&
-                newWindow.ClassName != "Windows.UI.Core.CoreWindow" && newWindow.ProcessName != _powerLauncherExe)
+                newWindow.ClassName != "Windows.UI.Core.CoreWindow" && newWindow.ProcessInfo.Name != _powerLauncherExe)
             {
-                windows.Add(newWindow);
+                // To hide (not add) preloaded uwp app windows that are invisible to the user we check the cloak state in DWM to be "none". (Issue #13637.)
+                // (If user asking to see these windows again we can add an optional plugin setting in the future.)
+                if (!newWindow.IsCloaked)
+                {
+                    windows.Add(newWindow);
+                }
             }
 
             return true;

src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/SearchController.cs

@@ -7,7 +7,6 @@ using System;
 using System.Collections.Generic;
 using System.Globalization;
 using System.Linq;
-using System.Threading.Tasks;
 
 namespace Microsoft.Plugin.WindowWalker.Components
 {
@@ -24,7 +23,7 @@ namespace Microsoft.Plugin.WindowWalker.Components
 
         /// <summary>
         /// Open window search results
-        /// </summary
+        /// </summary>
         private List<SearchResult> searchMatches;
 
         /// <summary>
@@ -32,16 +31,6 @@ namespace Microsoft.Plugin.WindowWalker.Components
         /// </summary>
         private static SearchController instance;
 
-        /// <summary>
-        /// Delegate handler for open windows updates
-        /// </summary>
-        public delegate void SearchResultUpdateEventHandler(object sender, SearchResultUpdateEventArgs e);
-
-        /// <summary>
-        /// Event raised when there is an update to the list of open windows
-        /// </summary>
-        public event SearchResultUpdateEventHandler OnSearchResultUpdateEventHandler;
-
         /// <summary>
         /// Gets or sets the current search text
         /// </summary>
@@ -95,16 +84,16 @@ namespace Microsoft.Plugin.WindowWalker.Components
         /// <summary>
         /// Event handler for when the search text has been updated
         /// </summary>
-        public async Task UpdateSearchText(string searchText)
+        public void UpdateSearchText(string searchText)
         {
             SearchText = searchText;
-            await SyncOpenWindowsWithModelAsync().ConfigureAwait(false);
+            SyncOpenWindowsWithModel();
         }
 
         /// <summary>
         /// Syncs the open windows with the OpenWindows Model
         /// </summary>
-        public async Task SyncOpenWindowsWithModelAsync()
+        public void SyncOpenWindowsWithModel()
         {
             System.Diagnostics.Debug.Print("Syncing WindowSearch result with OpenWindows Model");
 
@@ -116,22 +105,8 @@ namespace Microsoft.Plugin.WindowWalker.Components
             }
             else
             {
-                searchMatches = await FuzzySearchOpenWindowsAsync(snapshotOfOpenWindows).ConfigureAwait(false);
+                searchMatches = FuzzySearchOpenWindows(snapshotOfOpenWindows);
             }
-
-            OnSearchResultUpdateEventHandler?.Invoke(this, new SearchResultUpdateEventArgs());
-        }
-
-        /// <summary>
-        /// Redirecting method for Fuzzy searching
-        /// </summary>
-        /// <param name="openWindows">what windows are open</param>
-        /// <returns>Returns search results</returns>
-        private Task<List<SearchResult>> FuzzySearchOpenWindowsAsync(List<Window> openWindows)
-        {
-            return Task.Run(
-                () =>
-                    FuzzySearchOpenWindows(openWindows));
         }
 
         /// <summary>
@@ -151,7 +126,7 @@ namespace Microsoft.Plugin.WindowWalker.Components
                 foreach (var window in openWindows)
                 {
                     var titleMatch = FuzzyMatching.FindBestFuzzyMatch(window.Title, searchString.SearchText);
-                    var processMatch = FuzzyMatching.FindBestFuzzyMatch(window.ProcessName, searchString.SearchText);
+                    var processMatch = FuzzyMatching.FindBestFuzzyMatch(window.ProcessInfo.Name, searchString.SearchText);
 
                     if ((titleMatch.Count != 0 || processMatch.Count != 0) &&
                                 window.Title.Length != 0)

src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/Window.cs

@@ -7,9 +7,9 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Globalization;
-using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
+using Wox.Plugin.Logger;
 
 namespace Microsoft.Plugin.WindowWalker.Components
 {
@@ -18,22 +18,22 @@ namespace Microsoft.Plugin.WindowWalker.Components
     /// </summary>
     public class Window
     {
-        /// <summary>
-        /// Maximum size of a file name
-        /// </summary>
-        private const int MaximumFileNameLength = 1000;
-
-        /// <summary>
-        /// The list of owners of a window so that we don't have to
-        /// constantly query for the process owning a specific window
-        /// </summary>
-        private static readonly Dictionary<IntPtr, string> _handlesToProcessCache = new Dictionary<IntPtr, string>();
-
         /// <summary>
         /// The handle to the window
         /// </summary>
         private readonly IntPtr hwnd;
 
+        /// <summary>
+        /// A static cache for the process data of all known windows
+        /// that we don't have to query the data every time
+        /// </summary>
+        private static readonly Dictionary<IntPtr, WindowProcess> _handlesToProcessCache = new Dictionary<IntPtr, WindowProcess>();
+
+        /// <summary>
+        /// An instance of <see cref="WindowProcess"/> that contains the process information for the window
+        /// </summary>
+        private readonly WindowProcess processInfo;
+
         /// <summary>
         /// Gets the title of the window (the string displayed at the top of the window)
         /// </summary>
@@ -68,63 +68,12 @@ namespace Microsoft.Plugin.WindowWalker.Components
             get { return hwnd; }
         }
 
-        public uint ProcessID { get; set; }
-
         /// <summary>
-        /// Gets the name of the process
+        /// Gets the object of with the process information of the window
         /// </summary>
-        public string ProcessName
+        public WindowProcess ProcessInfo
         {
-            get
-            {
-                lock (_handlesToProcessCache)
-                {
-                    if (_handlesToProcessCache.Count > 7000)
-                    {
-                        Debug.Print("Clearing Process Cache because it's size is " + _handlesToProcessCache.Count);
-                        _handlesToProcessCache.Clear();
-                    }
-
-                    if (!_handlesToProcessCache.ContainsKey(Hwnd))
-                    {
-                        var processName = GetProcessNameFromWindowHandle(Hwnd);
-
-                        if (processName.Length != 0)
-                        {
-                            _handlesToProcessCache.Add(
-                                Hwnd,
-                                processName.ToString().Split('\\').Reverse().ToArray()[0]);
-                        }
-                        else
-                        {
-                            _handlesToProcessCache.Add(Hwnd, string.Empty);
-                        }
-                    }
-
-                    if (_handlesToProcessCache[hwnd].ToUpperInvariant() == "APPLICATIONFRAMEHOST.EXE")
-                    {
-                        new Task(() =>
-                        {
-                            NativeMethods.CallBackPtr callbackptr = new NativeMethods.CallBackPtr((IntPtr hwnd, IntPtr lParam) =>
-                            {
-                                var childProcessId = GetProcessIDFromWindowHandle(hwnd);
-                                if (childProcessId != ProcessID)
-                                {
-                                    _handlesToProcessCache[Hwnd] = GetProcessNameFromWindowHandle(hwnd);
-                                    return false;
-                                }
-                                else
-                                {
-                                    return true;
-                                }
-                            });
-                            _ = NativeMethods.EnumChildWindows(Hwnd, callbackptr, 0);
-                        }).Start();
-                    }
-
-                    return _handlesToProcessCache[hwnd];
-                }
-            }
+            get { return processInfo; }
         }
 
         /// <summary>
@@ -134,15 +83,7 @@ namespace Microsoft.Plugin.WindowWalker.Components
         {
             get
             {
-                StringBuilder windowClassName = new StringBuilder(300);
-                var numCharactersWritten = NativeMethods.GetClassName(Hwnd, windowClassName, windowClassName.MaxCapacity);
-
-                if (numCharactersWritten == 0)
-                {
-                    return string.Empty;
-                }
-
-                return windowClassName.ToString();
+                return GetWindowClassName(Hwnd);
             }
         }
 
@@ -157,6 +98,18 @@ namespace Microsoft.Plugin.WindowWalker.Components
             }
         }
 
+        /// <summary>
+        /// Gets a value indicating whether the window is cloaked (true) or not (false).
+        /// (A cloaked window is not visible to the user. But the window is still composed by DWM.)
+        /// </summary>
+        public bool IsCloaked
+        {
+            get
+            {
+                return GetWindowCloakState() != WindowCloakState.None;
+            }
+        }
+
         /// <summary>
         /// Gets a value indicating whether the specified window handle identifies an existing window.
         /// </summary>
@@ -236,6 +189,7 @@ namespace Microsoft.Plugin.WindowWalker.Components
         {
             // TODO: Add verification as to whether the window handle is valid
             this.hwnd = hwnd;
+            processInfo = CreateWindowProcessInstance(hwnd);
         }
 
         /// <summary>
@@ -248,7 +202,7 @@ namespace Microsoft.Plugin.WindowWalker.Components
             //    to use ShowWindow for switching tabs in IE
             // 2) SetForegroundWindow fails on minimized windows
             // Using Ordinal since this is internal
-            if (ProcessName.ToUpperInvariant().Equals("IEXPLORE.EXE", StringComparison.Ordinal) || !Minimized)
+            if (processInfo.Name.ToUpperInvariant().Equals("IEXPLORE.EXE", StringComparison.Ordinal) || !Minimized)
             {
                 NativeMethods.SetForegroundWindow(Hwnd);
             }
@@ -271,7 +225,7 @@ namespace Microsoft.Plugin.WindowWalker.Components
         public override string ToString()
         {
             // Using CurrentCulture since this is user facing
-            return Title + " (" + ProcessName.ToUpper(CultureInfo.CurrentCulture) + ")";
+            return Title + " (" + processInfo.Name.ToUpper(CultureInfo.CurrentCulture) + ")";
         }
 
         /// <summary>
@@ -309,36 +263,125 @@ namespace Microsoft.Plugin.WindowWalker.Components
         }
 
         /// <summary>
-        /// Gets the name of the process using the window handle
+        /// Returns the window cloak state from DWM
+        /// (A cloaked window is not visible to the user. But the window is still composed by DWM.)
         /// </summary>
-        /// <param name="hwnd">The handle to the window</param>
-        /// <returns>A string representing the process name or an empty string if the function fails</returns>
-        private string GetProcessNameFromWindowHandle(IntPtr hwnd)
+        /// <returns>The state (none, app, ...) of the window</returns>
+        public WindowCloakState GetWindowCloakState()
         {
-            uint processId = GetProcessIDFromWindowHandle(hwnd);
-            ProcessID = processId;
-            IntPtr processHandle = NativeMethods.OpenProcess(NativeMethods.ProcessAccessFlags.QueryLimitedInformation, true, (int)processId);
-            StringBuilder processName = new StringBuilder(MaximumFileNameLength);
+            _ = NativeMethods.DwmGetWindowAttribute(Hwnd, (int)NativeMethods.DwmWindowAttribute.Cloaked, out int isCloakedState, sizeof(uint));
 
-            if (NativeMethods.GetProcessImageFileName(processHandle, processName, MaximumFileNameLength) != 0)
+            switch (isCloakedState)
             {
-                return processName.ToString().Split('\\').Reverse().ToArray()[0];
-            }
-            else
-            {
-                return string.Empty;
+                case (int)NativeMethods.DwmWindowCloakState.None:
+                    return WindowCloakState.None;
+                case (int)NativeMethods.DwmWindowCloakState.CloakedApp:
+                    return WindowCloakState.App;
+                case (int)NativeMethods.DwmWindowCloakState.CloakedShell:
+                    return WindowCloakState.Shell;
+                case (int)NativeMethods.DwmWindowCloakState.CloakedInherited:
+                    return WindowCloakState.Inherited;
+                default:
+                    return WindowCloakState.Unknown;
             }
         }
 
         /// <summary>
-        /// Gets the process ID for the Window handle
+        /// Enum to simplify the cloak state of the window
         /// </summary>
-        /// <param name="hwnd">The handle to the window</param>
-        /// <returns>The process ID</returns>
-        private static uint GetProcessIDFromWindowHandle(IntPtr hwnd)
+        public enum WindowCloakState
         {
-            _ = NativeMethods.GetWindowThreadProcessId(hwnd, out uint processId);
-            return processId;
+            None,
+            App,
+            Shell,
+            Inherited,
+            Unknown,
+        }
+
+        /// <summary>
+        /// Returns the class name of a window.
+        /// </summary>
+        /// <param name="hwnd">Handle to the window.</param>
+        /// <returns>Class name</returns>
+        private static string GetWindowClassName(IntPtr hwnd)
+        {
+            StringBuilder windowClassName = new StringBuilder(300);
+            var numCharactersWritten = NativeMethods.GetClassName(hwnd, windowClassName, windowClassName.MaxCapacity);
+
+            if (numCharactersWritten == 0)
+            {
+                return string.Empty;
+            }
+
+            return windowClassName.ToString();
+        }
+
+        /// <summary>
+        /// Gets an instance of <see cref="WindowProcess"/> form process cache or creates a new one. A new one will be added to the cache.
+        /// </summary>
+        /// <param name="hWindow">The handle to the window</param>
+        /// <returns>A new Instance of type <see cref="WindowProcess"/></returns>
+        private static WindowProcess CreateWindowProcessInstance(IntPtr hWindow)
+        {
+            lock (_handlesToProcessCache)
+            {
+                if (_handlesToProcessCache.Count > 7000)
+                {
+                    Debug.Print("Clearing Process Cache because it's size is " + _handlesToProcessCache.Count);
+                    _handlesToProcessCache.Clear();
+                }
+
+                // Add window's process to cache if missing
+                if (!_handlesToProcessCache.ContainsKey(hWindow))
+                {
+                    // Get process ID and name
+                    var processId = WindowProcess.GetProcessIDFromWindowHandle(hWindow);
+                    var threadId = WindowProcess.GetThreadIDFromWindowHandle(hWindow);
+                    var processName = WindowProcess.GetProcessNameFromProcessID(processId);
+
+                    if (processName.Length != 0)
+                    {
+                        _handlesToProcessCache.Add(hWindow, new WindowProcess(processId, threadId, processName));
+                    }
+                    else
+                    {
+                        // For the dwm process we can not receive the name. This is no problem because the window isn't part of result list.
+                        Log.Debug($"Invalid process {processId} ({processName}) for window handle {hWindow}.", typeof(Window));
+                        _handlesToProcessCache.Add(hWindow, new WindowProcess(0, 0, string.Empty));
+                    }
+                }
+
+                // Correct the process data if the window belongs to a uwp app hosted by 'ApplicationFrameHost.exe'
+                // (This only works if the window isn't minimized. For minimized windows the required child window isn't assigned.)
+                if (_handlesToProcessCache[hWindow].Name.ToUpperInvariant() == "APPLICATIONFRAMEHOST.EXE")
+                {
+                    new Task(() =>
+                    {
+                        NativeMethods.CallBackPtr callbackptr = new NativeMethods.CallBackPtr((IntPtr hwnd, IntPtr lParam) =>
+                        {
+                            // Every uwp app main window has at least three child windows. Only the one we are interested in has a class starting with "Windows.UI.Core." and is assigned to the real app process.
+                            // (The other ones have a class name that begins with the string "ApplicationFrame".)
+                            if (GetWindowClassName(hwnd).StartsWith("Windows.UI.Core.", StringComparison.OrdinalIgnoreCase))
+                            {
+                                var childProcessId = WindowProcess.GetProcessIDFromWindowHandle(hwnd);
+                                var childThreadId = WindowProcess.GetThreadIDFromWindowHandle(hwnd);
+                                var childProcessName = WindowProcess.GetProcessNameFromProcessID(childProcessId);
+
+                                // Update process info in cache
+                                _handlesToProcessCache[hWindow].UpdateProcessInfo(childProcessId, childThreadId, childProcessName);
+                                return false;
+                            }
+                            else
+                            {
+                                return true;
+                            }
+                        });
+                        _ = NativeMethods.EnumChildWindows(hWindow, callbackptr, 0);
+                    }).Start();
+                }
+
+                return _handlesToProcessCache[hWindow];
+            }
         }
     }
 }

src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/WindowProcess.cs

@@ -0,0 +1,200 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+using System;
+using System.Diagnostics;
+using System.Linq;
+using System.Text;
+
+namespace Microsoft.Plugin.WindowWalker.Components
+{
+    /// <summary>
+    /// Represents the process data of an open window. This class is used in the process cache and for the process object of the open window
+    /// </summary>
+    public class WindowProcess
+    {
+        /// <summary>
+        /// Maximum size of a file name
+        /// </summary>
+        private const int MaximumFileNameLength = 1000;
+
+        /// <summary>
+        /// An indicator if the window belongs to an 'Universal Windows Platform (UWP)' process
+        /// </summary>
+        private readonly bool _isUwpApp;
+
+        /// <summary>
+        /// Gets the id of the process
+        /// </summary>
+        public uint ProcessID
+        {
+            get; private set;
+        }
+
+        /// <summary>
+        /// Gets the id of the thread
+        /// </summary>
+        public uint ThreadID
+        {
+            get; private set;
+        }
+
+        /// <summary>
+        /// Gets the name of the process
+        /// </summary>
+        public string Name
+        {
+            get; private set;
+        }
+
+        /// <summary>
+        /// Gets a value indicating whether the window belongs to an 'Universal Windows Platform (UWP)' process
+        /// </summary>
+        public bool IsUwpApp
+        {
+            get { return _isUwpApp; }
+        }
+
+        /// <summary>
+        /// Gets a value indicating whether this is the shell process or not
+        /// The shell process (like explorer.exe) hosts parts of the user interface (like taskbar, start menu, ...)
+        /// </summary>
+        public bool IsShellProcess
+        {
+            get
+            {
+                IntPtr hShellWindow = NativeMethods.GetShellWindow();
+                return GetProcessIDFromWindowHandle(hShellWindow) == ProcessID;
+            }
+        }
+
+        /// <summary>
+        /// Gets a value indicating whether the process exists on the machine
+        /// </summary>
+        public bool DoesExist
+        {
+            get
+            {
+                try
+                {
+                    var p = Process.GetProcessById((int)ProcessID);
+                    p.Dispose();
+                    return true;
+                }
+                catch (InvalidOperationException)
+                {
+                    // Thrown when process not exist.
+                    return false;
+                }
+                catch (ArgumentException)
+                {
+                    // Thrown when process not exist.
+                    return false;
+                }
+            }
+        }
+
+        /// <summary>
+        /// Gets a value indicating whether full access to the process is denied or not
+        /// </summary>
+        public bool IsFullAccessDenied
+        {
+            get; private set;
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="WindowProcess"/> class.
+        /// </summary>
+        /// <param name="pid">New process id.</param>
+        /// <param name="tid">New thread id.</param>
+        /// <param name="name">New process name.</param>
+        public WindowProcess(uint pid, uint tid, string name)
+        {
+            UpdateProcessInfo(pid, tid, name);
+            _isUwpApp = Name.ToUpperInvariant().Equals("APPLICATIONFRAMEHOST.EXE", StringComparison.Ordinal);
+        }
+
+        /// <summary>
+        /// Updates the process information of the <see cref="WindowProcess"/> instance.
+        /// </summary>
+        /// <param name="pid">New process id.</param>
+        /// <param name="tid">New thread id.</param>
+        /// <param name="name">New process name.</param>
+        public void UpdateProcessInfo(uint pid, uint tid, string name)
+        {
+            // TODO: Add verification as to wether the process id and thread id is valid
+            ProcessID = pid;
+            ThreadID = tid;
+            Name = name;
+
+            // Process can be elevated only if process id is not 0 (Dummy value on error)
+            IsFullAccessDenied = (pid != 0) ? TestProcessAccessUsingAllAccessFlag(pid) : false;
+        }
+
+        /// <summary>
+        /// Gets the process ID for the window handle
+        /// </summary>
+        /// <param name="hwnd">The handle to the window</param>
+        /// <returns>The process ID</returns>
+        public static uint GetProcessIDFromWindowHandle(IntPtr hwnd)
+        {
+            _ = NativeMethods.GetWindowThreadProcessId(hwnd, out uint processId);
+            return processId;
+        }
+
+        /// <summary>
+        /// Gets the thread ID for the window handle
+        /// </summary>
+        /// <param name="hwnd">The handle to the window</param>
+        /// <returns>The thread ID</returns>
+        public static uint GetThreadIDFromWindowHandle(IntPtr hwnd)
+        {
+            uint threadId = NativeMethods.GetWindowThreadProcessId(hwnd, out _);
+            return threadId;
+        }
+
+        /// <summary>
+        /// Gets the process name for the process ID
+        /// </summary>
+        /// <param name="pid">The id of the process/param>
+        /// <returns>A string representing the process name or an empty string if the function fails</returns>
+        public static string GetProcessNameFromProcessID(uint pid)
+        {
+            IntPtr processHandle = NativeMethods.OpenProcess(NativeMethods.ProcessAccessFlags.QueryLimitedInformation, true, (int)pid);
+            StringBuilder processName = new StringBuilder(MaximumFileNameLength);
+
+            if (NativeMethods.GetProcessImageFileName(processHandle, processName, MaximumFileNameLength) != 0)
+            {
+                _ = NativeMethods.CloseHandleIfNotNull(processHandle);
+                return processName.ToString().Split('\\').Reverse().ToArray()[0];
+            }
+            else
+            {
+                _ = NativeMethods.CloseHandleIfNotNull(processHandle);
+                return string.Empty;
+            }
+        }
+
+        /// <summary>
+        /// Gets a boolean value indicating whether the access to a process using the AllAccess flag is denied or not.
+        /// </summary>
+        /// <param name="pid">The process ID of the process</param>
+        /// <returns>True if denied and false if not.</returns>
+        private static bool TestProcessAccessUsingAllAccessFlag(uint pid)
+        {
+            IntPtr processHandle = NativeMethods.OpenProcess(NativeMethods.ProcessAccessFlags.AllAccess, true, (int)pid);
+
+            if (NativeMethods.GetLastWin32Error() == 5)
+            {
+                // Error 5 = ERROR_ACCESS_DENIED
+                _ = NativeMethods.CloseHandleIfNotNull(processHandle);
+                return true;
+            }
+            else
+            {
+                _ = NativeMethods.CloseHandleIfNotNull(processHandle);
+                return false;
+            }
+        }
+    }
+}

src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Main.cs

@@ -13,8 +13,6 @@ namespace Microsoft.Plugin.WindowWalker
 {
     public class Main : IPlugin, IPluginI18n
     {
-        private static List<SearchResult> _results = new List<SearchResult>();
-
         private string IconPath { get; set; }
 
         private PluginInitContext Context { get; set; }
@@ -25,7 +23,6 @@ namespace Microsoft.Plugin.WindowWalker
 
         static Main()
         {
-            SearchController.Instance.OnSearchResultUpdateEventHandler += SearchResultUpdated;
             OpenWindows.Instance.UpdateOpenWindowsList();
         }
 
@@ -37,18 +34,22 @@ namespace Microsoft.Plugin.WindowWalker
             }
 
             OpenWindows.Instance.UpdateOpenWindowsList();
-            SearchController.Instance.UpdateSearchText(query.Search).Wait();
+            SearchController.Instance.UpdateSearchText(query.Search);
+            List<SearchResult> searchControllerResults = SearchController.Instance.SearchMatches;
 
-            return _results.Select(x => new Result()
+            return searchControllerResults.Select(x => new Result()
             {
                 Title = x.Result.Title,
                 IcoPath = IconPath,
-                SubTitle = Properties.Resources.wox_plugin_windowwalker_running + ": " + x.Result.ProcessName,
+                SubTitle = Properties.Resources.wox_plugin_windowwalker_running + ": " + x.Result.ProcessInfo.Name,
                 Action = c =>
                 {
                     x.Result.SwitchToWindow();
                     return true;
                 },
+
+                // For debugging you can remove the comment sign in the next line.
+                // ToolTipData = new ToolTipData(x.Result.Title, $"hWnd: {x.Result.Hwnd}\nWindow class: {x.Result.ClassName}\nProcess ID: {x.Result.ProcessInfo.ProcessID}\nThread ID: {x.Result.ProcessInfo.ThreadID}\nProcess: {x.Result.ProcessInfo.Name}\nProcess exists: {x.Result.ProcessInfo.DoesExist}\nIs full access denied: {x.Result.ProcessInfo.IsFullAccessDenied}\nIs uwp app: {x.Result.ProcessInfo.IsUwpApp}\nIs ShellProcess: {x.Result.ProcessInfo.IsShellProcess}\nIs window cloaked: {x.Result.IsCloaked}\nWindow cloak state: {x.Result.GetWindowCloakState()}"),
             }).ToList();
         }
 
@@ -86,10 +87,5 @@ namespace Microsoft.Plugin.WindowWalker
         {
             return Properties.Resources.wox_plugin_windowwalker_plugin_description;
         }
-
-        private static void SearchResultUpdated(object sender, SearchController.SearchResultUpdateEventArgs e)
-        {
-            _results = SearchController.Instance.SearchMatches;
-        }
     }
 }