diff --git a/NTwain/TwainSessionBase.cs b/NTwain/TwainSessionBase.cs
index 5886ff1..eca15d9 100644
--- a/NTwain/TwainSessionBase.cs
+++ b/NTwain/TwainSessionBase.cs
@@ -576,9 +576,10 @@ namespace NTwain
 
                     TWEvent evt = new TWEvent();
                     evt.pEvent = msgPtr;
-                    handled = DGControl.Event.ProcessEvent(evt) == ReturnCode.DSEvent;
-                    
-                    HandleSourceMsg(evt.TWMessage);
+                    if (handled = DGControl.Event.ProcessEvent(evt) == ReturnCode.DSEvent)
+                    {
+                        HandleSourceMsg(evt.TWMessage);
+                    }
                 }
                 finally
                 {
@@ -604,7 +605,7 @@ namespace NTwain
                     var ctx = o as SynchronizationContext;
                     if (ctx != null)
                     {
-                        _syncer.Send(blah =>
+                        _syncer.Post(blah =>
                         {
                             HandleSourceMsg(msg);
                         }, null);
@@ -623,10 +624,7 @@ namespace NTwain
         // method that handles msg from the source, whether it's from wndproc or callbacks
         void HandleSourceMsg(Message msg)
         {
-            if (msg != Message.Null)
-            {
-                Debug.WriteLine(string.Format("Thread {0}: HandleSourceMsg at state {1} with MSG={2}.", Thread.CurrentThread.ManagedThreadId, State, msg));
-            }
+            Debug.WriteLine(string.Format("Thread {0}: HandleSourceMsg at state {1} with MSG={2}.", Thread.CurrentThread.ManagedThreadId, State, msg));
 
             switch (msg)
             {
diff --git a/Tests/Tester.WPF/MainWindow.xaml.cs b/Tests/Tester.WPF/MainWindow.xaml.cs
index 44ae85b..9a040ab 100644
--- a/Tests/Tester.WPF/MainWindow.xaml.cs
+++ b/Tests/Tester.WPF/MainWindow.xaml.cs
@@ -18,6 +18,7 @@ using System.Windows.Interop;
 using System.Runtime.InteropServices;
 using CommonWin32;
 using System.Threading;
+using ModernWPF.Controls;
 
 namespace Tester.WPF
 {
@@ -79,7 +80,7 @@ namespace Tester.WPF
                 var rc2 = twain.CloseSource();
                 rc2 = twain.CloseManager();
 
-                MessageBox.Show("Success!");
+                ModernMessageBox.Show(this, "Success!");
             };
             twain.TransferReady += (s, te) =>
             {
@@ -92,7 +93,7 @@ namespace Tester.WPF
                 //}
                 //else
                 //{
-                    //te.OutputFile = System.IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "test.bmp");
+                //te.OutputFile = System.IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "test.bmp");
                 //}
             };
         }
@@ -157,7 +158,7 @@ namespace Tester.WPF
                 twain.DGControl.Status.GetManager(out status);
             }
 
-            MessageBox.Show(string.Format("Step {0}: RC={1}, CC={2}", step, rc, status.ConditionCode));
+            ModernMessageBox.Show(this, string.Format("Step {0}: RC={1}, CC={2}", step, rc, status.ConditionCode));
         }
     }
 }