Work around bug in WPF when running in .NET Core

See dotnet/wpf#4181 and dotnet/wpf#7345 for more information.

src/Eto.WinForms/Win32.cs

@@ -632,5 +632,8 @@ public struct SCROLLINFO
 
 		[DllImport("User32.dll", SetLastError = true)]
     	public static extern int SetWindowRgn(IntPtr hWnd, IntPtr hRgn, bool bRedraw);
+
+		[DllImport("kernel32.dll")]
+		public static extern void SetLastError(uint dwErrCode);
 	}
 }

src/Eto.Wpf/Forms/DialogHandler.cs

@@ -1,14 +1,51 @@
+using System.Windows.Automation.Peers;
 using Eto.Wpf.Forms.Controls;
 namespace Eto.Wpf.Forms
 {
+	class EtoWindowAutomationPeer : WindowAutomationPeer
+	{
+		public EtoWindowAutomationPeer(sw.Window owner) : base(owner)
+		{
+		}
+
+		protected override string GetNameCore()
+		{
+			try
+			{
+				// due to windows message hooks, we can already be in error state which causes exceptions here.
+#if NET
+				Marshal.SetLastSystemError(0);
+#else
+				Win32.SetLastError(0);
+#endif
+				return base.GetNameCore();
+			}
+			catch (Win32Exception)
+			{
+				// See https://github.com/dotnet/wpf/issues/4181 and https://github.com/dotnet/wpf/pull/7345
+				// Until that fix is in, we fix it ourselves to avoid random crashes
+				return (Owner as sw.Window)?.Title ?? string.Empty;
+			}
+		}
+	}
+
+
+	public class EtoWindow : sw.Window
+	{
+		protected override AutomationPeer OnCreateAutomationPeer()
+		{
+			return new EtoWindowAutomationPeer(this);
+		}
+	}
+
 	public class DialogHandler : WpfWindow<sw.Window, Dialog, Dialog.ICallback>, Dialog.IHandler
 	{
 		Button defaultButton;
 		Rectangle? parentWindowBounds;
 		swc.DockPanel dockMain;
 		swc.Grid gridButtons;
 
-		public DialogHandler() : this(new sw.Window()) { }
+		public DialogHandler() : this(new EtoWindow()) { }
 
 		public DialogHandler(sw.Window window)
 		{

src/Eto.Wpf/Forms/FormHandler.cs

@@ -1,41 +1,40 @@
 namespace Eto.Wpf.Forms
 {
-	public class FormHandler : WpfWindow<sw.Window, Form, Form.ICallback>, Form.IHandler
+	public class EtoFormWindow : EtoWindow
 	{
-		public class EtoWindow : sw.Window
+		public EtoFormWindow()
 		{
+			AllowDrop = true;
+		}
 
-			public EtoWindow()
-			{
-				AllowDrop = true;
-			}
-
-			protected override void OnActivated(EventArgs e)
-			{
-				if (!Focusable)
-					return;
-				base.OnActivated(e);
-			}
+		protected override void OnActivated(EventArgs e)
+		{
+			if (!Focusable)
+				return;
+			base.OnActivated(e);
+		}
 
-			protected override void OnPreviewGotKeyboardFocus(swi.KeyboardFocusChangedEventArgs e)
+		protected override void OnPreviewGotKeyboardFocus(swi.KeyboardFocusChangedEventArgs e)
+		{
+			if (!Focusable)
 			{
-				if (!Focusable)
-				{
-					e.Handled = true;
-					return;
-				}
-				base.OnPreviewGotKeyboardFocus(e);
+				e.Handled = true;
+				return;
 			}
+			base.OnPreviewGotKeyboardFocus(e);
 		}
-
+	}
+
+	public class FormHandler : WpfWindow<sw.Window, Form, Form.ICallback>, Form.IHandler
+	{
 		public FormHandler(sw.Window window)
 		{
 			Control = window;
 		}
 
 		public FormHandler()
 		{
-			Control = new EtoWindow();
+			Control = new EtoFormWindow();
 		}
 
 		public virtual void Show()