Calling Game.Exit didn't exit the run loop

as it only exited if a WM_QUIT message was sent.  Now disposes of the underlying form when Game.Exit is called.  This breaks it out of the run loop.

MonoGame.Framework/Windows/WinFormsGamePlatform.cs

@@ -133,8 +133,10 @@ public override void StartRunLoop()
         }
 
         public override void Exit()
-        {
-            Application.Exit();
+        {
+            _window.Dispose();
+            _window = null;
+            Window = null;
         }
 
         public override bool BeforeUpdate(GameTime gameTime)
@@ -189,9 +191,8 @@ protected override void Dispose(bool disposing)
                     _window.Dispose();
                     _window = null;
                     Window = null;
-
-                    Microsoft.Xna.Framework.Media.MediaManagerState.CheckShutdown();
-                }
+                }
+                Microsoft.Xna.Framework.Media.MediaManagerState.CheckShutdown();
             }
 
             base.Dispose(disposing);

MonoGame.Framework/Windows/WinFormsGameWindow.cs

@@ -59,7 +59,7 @@ 1. Definitions
 
 namespace MonoGame.Framework
 {
-    class WinFormsGameWindow : GameWindow
+    class WinFormsGameWindow : GameWindow, IDisposable
     {
         internal WinFormsGameForm _form;
 
@@ -198,6 +198,11 @@ internal WinFormsGameWindow(WinFormsGamePlatform platform)
             _allWindows.Add(this);
         }
 
+        ~WinFormsGameWindow()
+        {
+            Dispose(false);
+        }
+
         private void OnActivated(object sender, EventArgs eventArgs)
         {
             _platform.IsActive = true;
@@ -377,7 +382,8 @@ internal void RunLoop()
                     continue;
                 }
 
-                OnIdle(this, null);
+                UpdateWindows();
+                Game.Tick();
             }
 
             // We need to remove the WM_QUIT message in the message 
@@ -399,18 +405,6 @@ internal void RunLoop()
             while (PeekMessage(out msg, IntPtr.Zero, 0, 0, 1));
         }
 
-        private void OnIdle(object sender, EventArgs eventArgs)
-        {
-            // While there are no pending messages 
-            // to be processed tick the game.
-            NativeMessage msg;
-            while (!PeekMessage(out msg, IntPtr.Zero, 0, 0, 0))
-            {
-                UpdateWindows();
-                Game.Tick();
-            }
-        }
-
         internal void UpdateWindows()
         {
             // Update the mouse state for each window.
@@ -444,11 +438,20 @@ internal void ChangeClientSize(Size clientBounds)
 
         public void Dispose()
         {
-            if (_form != null)
+            Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+
+        void Dispose(bool disposing)
+        {
+            if (disposing)
             {
-                _allWindows.Remove(this);
-                _form.Dispose();
-                _form = null;
+                if (_form != null)
+                {
+                    _allWindows.Remove(this);
+                    _form.Dispose();
+                    _form = null;
+                }
             }
         }