Fix window handle provider.

zaaReloaded2/ThisAddIn.cs

@@ -69,6 +69,10 @@ namespace zaaReloaded2
             }
 
             Bovender.ExceptionHandler.CentralHandler.ManageExceptionCallback += CentralHandler_ManageExceptionCallback;
+            Bovender.Win32Window.MainWindowHandleProvider = () =>
+            {
+                return IntPtr.Zero;
+            };
             Bovender.WpfHelpers.RegisterTextBoxSelectAll();
             UserSettings userSettings = UserSettings.Default;