From f33768240e3f86777aa154b03aed5db208299eba Mon Sep 17 00:00:00 2001
From: Phyxion <>
Date: Fri, 17 Jan 2020 13:01:37 +0100
Subject: [PATCH] Fix #190

---
 LibreHardwareMonitor/UI/ShowDesktop.cs | 87 ++++++++++++++++----------
 1 file changed, 54 insertions(+), 33 deletions(-)

diff --git a/LibreHardwareMonitor/UI/ShowDesktop.cs b/LibreHardwareMonitor/UI/ShowDesktop.cs
index 867e998..a52705d 100644
--- a/LibreHardwareMonitor/UI/ShowDesktop.cs
+++ b/LibreHardwareMonitor/UI/ShowDesktop.cs
@@ -9,30 +9,71 @@ using System.Windows.Forms;
 
 namespace LibreHardwareMonitor.UI
 {
-    public class ShowDesktop
+    public class ShowDesktop : IDisposable
     {
-        public delegate void ShowDesktopChangedEventHandler(bool showDesktop);
-        private event ShowDesktopChangedEventHandler ShowDesktopChangedEvent;
+        private readonly NativeWindow _referenceWindow;
+        private readonly string _referenceWindowCaption = "LibreHardwareMonitorShowDesktopReferenceWindow";
         private readonly System.Threading.Timer _timer;
         private bool _showDesktop;
-        private readonly string _referenceWindowCaption = "LibreHardwareMonitorShowDesktopReferenceWindow";
 
+        /// <summary>
+        /// Prevents a default instance of the <see cref="ShowDesktop" /> class from being created.
+        /// </summary>
         private ShowDesktop()
         {
-            // create a reference window to detect show desktop
-            NativeWindow referenceWindow = new NativeWindow();
+            // Create a reference window to detect show desktop
+            _referenceWindow = new NativeWindow();
+
             CreateParams cp = new CreateParams { ExStyle = GadgetWindow.WS_EX_TOOLWINDOW, Caption = _referenceWindowCaption };
-            referenceWindow.CreateHandle(cp);
-            NativeMethods.SetWindowPos(
-                referenceWindow.Handle,
-                GadgetWindow.HWND_BOTTOM, 0, 0, 0, 0, GadgetWindow.SWP_NOMOVE |
-                GadgetWindow.SWP_NOSIZE | GadgetWindow.SWP_NOACTIVATE |
-                GadgetWindow.SWP_NOSENDCHANGING);
+            _referenceWindow.CreateHandle(cp);
+            NativeMethods.SetWindowPos(_referenceWindow.Handle,
+                                       GadgetWindow.HWND_BOTTOM,
+                                       0,
+                                       0,
+                                       0,
+                                       0,
+                                       GadgetWindow.SWP_NOMOVE |
+                                       GadgetWindow.SWP_NOSIZE |
+                                       GadgetWindow.SWP_NOACTIVATE |
+                                       GadgetWindow.SWP_NOSENDCHANGING);
 
             // start a repeated timer to detect "Show Desktop" events
             _timer = new System.Threading.Timer(OnTimer, null, System.Threading.Timeout.Infinite, System.Threading.Timeout.Infinite);
         }
 
+        public delegate void ShowDesktopChangedEventHandler(bool showDesktop);
+
+        private event ShowDesktopChangedEventHandler ShowDesktopChangedEvent;
+
+        // notify when the "show desktop" mode is changed
+        public event ShowDesktopChangedEventHandler ShowDesktopChanged
+        {
+            add
+            {
+                // start the monitor timer when someone is listening
+                if (ShowDesktopChangedEvent == null)
+                    StartTimer();
+
+                ShowDesktopChangedEvent += value;
+            }
+            remove
+            {
+                ShowDesktopChangedEvent -= value;
+                // stop the monitor timer if nobody is interested
+                if (ShowDesktopChangedEvent == null)
+                    StopTimer();
+            }
+        }
+
+        public static ShowDesktop Instance { get; } = new ShowDesktop();
+
+        /// <inheritdoc />
+        public void Dispose()
+        {
+            _timer?.Dispose();
+            _referenceWindow.ReleaseHandle();
+        }
+
         private void StartTimer()
         {
             _timer.Change(0, 200);
@@ -68,6 +109,7 @@ namespace LibreHardwareMonitor.UI
                     }
                 }
             }
+
             return IntPtr.Zero;
         }
 
@@ -95,27 +137,6 @@ namespace LibreHardwareMonitor.UI
             }
         }
 
-        public static ShowDesktop Instance { get; } = new ShowDesktop();
-
-        // notify when the "show desktop" mode is changed
-        public event ShowDesktopChangedEventHandler ShowDesktopChanged
-        {
-            add
-            {
-                // start the monitor timer when someone is listening
-                if (ShowDesktopChangedEvent == null)
-                    StartTimer();
-                ShowDesktopChangedEvent += value;
-            }
-            remove
-            {
-                ShowDesktopChangedEvent -= value;
-                // stop the monitor timer if nobody is interested
-                if (ShowDesktopChangedEvent == null)
-                    StopTimer();
-            }
-        }
-
         private static class NativeMethods
         {
             private const string USER = "user32.dll";