Dispatcher.PushFrame: clean references before return

The dispatcher did not clean references before returning, therefore
the second call to Dispatcher.Run() failed.

2 files changed, 16 insertions, 0 deletions

diff --git a/mcs/class/WindowsBase/System.Windows.Threading/Dispatcher.cs b/mcs/class/WindowsBase/System.Windows.Threading/Dispatcher.cs
index 031f8081e87..f9c11ccc8fe 100644
--- a/mcs/class/WindowsBase/System.Windows.Threading/Dispatcher.cs
+++ b/mcs/class/WindowsBase/System.Windows.Threading/Dispatcher.cs
@@ -358,6 +358,10 @@ namespace System.Windows.Threading {
 			frame.dispatcher = dis;
 
 			dis.RunFrame (frame);
+
+			frame.dispatcher = null;
+			dis.current_frame = frame.ParentFrame;
+			frame.ParentFrame = null;
 		}
 
 		void PerformShutdown ()
diff --git a/mcs/class/WindowsBase/Test/System.Windows.Threading/DispatcherTest.cs b/mcs/class/WindowsBase/Test/System.Windows.Threading/DispatcherTest.cs
index 614cef51a43..0980ebb12ba 100644
--- a/mcs/class/WindowsBase/Test/System.Windows.Threading/DispatcherTest.cs
+++ b/mcs/class/WindowsBase/Test/System.Windows.Threading/DispatcherTest.cs
@@ -149,6 +149,18 @@ namespace MonoTests.System.Windows.Threading
 
 			Dispatcher.PushFrame(frame);
 		}
+
+		[Test]
+		public void TestRunTwice()
+		{
+			Dispatcher d = Dispatcher.CurrentDispatcher;
+			Action exit = delegate { Dispatcher.ExitAllFrames(); };
+
+			d.BeginInvoke(DispatcherPriority.Normal, exit);
+			Dispatcher.Run();
+			d.BeginInvoke(DispatcherPriority.Normal, exit);
+			Dispatcher.Run();
+		}
 	}
 }