diff --git a/Src/LexText/LexTextDll/AreaListener.cs b/Src/LexText/LexTextDll/AreaListener.cs
index 6d36ee52ca..287c2e0778 100644
--- a/Src/LexText/LexTextDll/AreaListener.cs
+++ b/Src/LexText/LexTextDll/AreaListener.cs
@@ -129,6 +129,7 @@ protected virtual void Dispose(bool disposing)
 			{
 				Subscriber.Unsubscribe(EventConstants.SetToolFromName, SetToolFromName);
 				Subscriber.Unsubscribe(EventConstants.ReloadAreaTools, ReloadAreaTools);
+				Subscriber.Unsubscribe(EventConstants.GetContentControlParameters, GetContentControlParameters);
 
 				// Dispose managed resources here.
 				if (m_mediator != null)
@@ -153,6 +154,7 @@ public void Init(Mediator mediator, PropertyTable propertyTable, XmlNode configu
 			m_ccustomLists = 0;
 			Subscriber.Subscribe(EventConstants.SetToolFromName, SetToolFromName);
 			Subscriber.Subscribe(EventConstants.ReloadAreaTools, ReloadAreaTools);
+			Subscriber.Subscribe(EventConstants.GetContentControlParameters, GetContentControlParameters);
 		}
 
 		private DateTime m_lastToolChange = DateTime.MinValue;
@@ -959,15 +961,18 @@ private XmlNode GetToolNodeForArea(string areaName, out string toolName)
 		}
 
 		/// <summary>
-		/// This is designed to be called by reflection through the mediator, when something typically in xWorks needs to get
-		/// the parameter node for a given tool. The last argument is a one-item array used to return the result,
-		/// since I don't think we handle Out parameters in our SendMessage protocol.
+		/// This subscriber is called when the GetContentControlParameters event is published.
+		/// Typically used when something in xWorks needs to get the parameter node for a given tool.
+		/// The last argument is a one-item array used to return the result because we
+		/// don't have return values or out parameters in our Publish/Subscribe protocol.
 		/// </summary>
-		public bool OnGetContentControlParameters(object parameterObj)
+		private void GetContentControlParameters(object parameterObj)
 		{
 			var param = parameterObj as Tuple<string, string, XmlNode[]>;
 			if (param == null)
-				return false; // we sure can't handle it; should we throw?
+			{
+				return; // we sure can't handle it; should we throw?
+			}
 			string area = param.Item1;
 			string tool = param.Item2;
 			XmlNode[] result = param.Item3;
@@ -976,7 +981,6 @@ public bool OnGetContentControlParameters(object parameterObj)
 			{
 				result[0] = node.SelectSingleNode("control");
 			}
-			return true; // whatever happened, we did the best that can be done.
 		}
 
 		protected string GetCurrentAreaName()
diff --git a/Src/xWorks/DictionaryConfigurationMigrators/PreHistoricMigrator.cs b/Src/xWorks/DictionaryConfigurationMigrators/PreHistoricMigrator.cs
index e70ff19271..33e86850c1 100644
--- a/Src/xWorks/DictionaryConfigurationMigrators/PreHistoricMigrator.cs
+++ b/Src/xWorks/DictionaryConfigurationMigrators/PreHistoricMigrator.cs
@@ -13,6 +13,7 @@
 using SIL.FieldWorks.Common.Controls;
 using SIL.LCModel.Core.KernelInterfaces;
 using SIL.FieldWorks.Common.FwUtils;
+using static SIL.FieldWorks.Common.FwUtils.FwUtils;
 using SIL.FieldWorks.Common.Widgets;
 using SIL.LCModel;
 using SIL.LCModel.DomainServices;
@@ -127,7 +128,7 @@ private XmlNode GetConfigureLayoutsNodeForTool(string tool)
 		{
 			var collector = new XmlNode[1];
 			var parameter = new Tuple<string, string, XmlNode[]>("lexicon", tool, collector);
-			m_mediator.SendMessage("GetContentControlParameters", parameter);
+			Publisher.Publish(new PublisherParameterObject(EventConstants.GetContentControlParameters, parameter));
 			var controlNode = collector[0];
 			var parameters = controlNode.SelectSingleNode("parameters");
 			var configureLayouts = XmlUtils.FindNode(parameters, "configureLayouts");
diff --git a/Src/xWorks/ExportDialog.cs b/Src/xWorks/ExportDialog.cs
index b34741bc8f..47e5b84684 100644
--- a/Src/xWorks/ExportDialog.cs
+++ b/Src/xWorks/ExportDialog.cs
@@ -519,7 +519,7 @@ private Control EnsureViewInfo()
 			}
 			var collector = new XmlNode[1];
 			var parameter = new Tuple<string, string, XmlNode[]>(area, tool, collector);
-			m_mediator.SendMessage("GetContentControlParameters", parameter);
+			Publisher.Publish(new PublisherParameterObject(EventConstants.GetContentControlParameters, parameter));
 			var controlNode = collector[0];
 			Debug.Assert(controlNode != null);
 			XmlNode dynLoaderNode = controlNode.SelectSingleNode("dynamicloaderinfo");
diff --git a/Src/xWorks/xWorksTests/DictionaryConfigurationMigrators/StubContentControlProvider.cs b/Src/xWorks/xWorksTests/DictionaryConfigurationMigrators/StubContentControlProvider.cs
index 2fcb328dcb..987dfba3b8 100644
--- a/Src/xWorks/xWorksTests/DictionaryConfigurationMigrators/StubContentControlProvider.cs
+++ b/Src/xWorks/xWorksTests/DictionaryConfigurationMigrators/StubContentControlProvider.cs
@@ -5,6 +5,8 @@
 using System;
 using System.Xml;
 using NUnit.Framework;
+using SIL.FieldWorks.Common.FwUtils;
+using static SIL.FieldWorks.Common.FwUtils.FwUtils;
 using XCore;
 
 namespace SIL.FieldWorks.XWorks.DictionaryConfigurationMigrators
@@ -14,7 +16,7 @@ namespace SIL.FieldWorks.XWorks.DictionaryConfigurationMigrators
 	/// tools for testing export functionality.
 	/// </summary>
 	/// <remarks>To use add the following to your TestFixtureSetup: m_mediator.AddColleague(new StubContentControlProvider());</remarks>
-	internal class StubContentControlProvider : IxCoreColleague
+	internal class StubContentControlProvider : IxCoreColleague, IDisposable
 	{
 		private const string m_contentControlDictionary =
 			@"<control>
@@ -63,6 +65,7 @@ public StubContentControlProvider()
 			var reversalDoc = new XmlDocument();
 			reversalDoc.LoadXml(m_contentControlReversal);
 			m_testControlRevNode = reversalDoc.DocumentElement;
+			Subscriber.Subscribe(EventConstants.GetContentControlParameters, GetContentControlParameters);
 		}
 
 		public void Init(Mediator mediator, PropertyTable propertyTable, XmlNode configurationParameters)
@@ -78,18 +81,34 @@ public IxCoreColleague[] GetMessageTargets()
 		/// This is called by reflection through the mediator. We need so that we can migrate through the PreHistoricMigrator.
 		/// </summary>
 		// ReSharper disable once UnusedMember.Local
-		private bool OnGetContentControlParameters(object parameterObj)
+		private void GetContentControlParameters(object parameterObj)
 		{
 			var param = parameterObj as Tuple<string, string, XmlNode[]>;
 			if (param == null)
-				return false;
+				return;
 			var result = param.Item3;
 			Assert.That(param.Item2 == "lexiconDictionary" || param.Item2 == "reversalToolEditComplete", "No params for tool: " + param.Item2);
 			result[0] = param.Item2 == "lexiconDictionary" ? m_testControlDictNode : m_testControlRevNode;
-			return true;
 		}
 
 		public bool ShouldNotCall { get { return false; } }
 		public int Priority { get { return 1; }}
+
+		public void Dispose()
+		{
+			GC.SuppressFinalize(this);
+			Dispose(true);
+		}
+
+		public void Dispose(bool disposeCalled)
+		{
+			System.Diagnostics.Debug.WriteLineIf(!disposeCalled, "****** Missing Dispose() call for " + GetType().Name + ". ****** ");
+			Subscriber.Unsubscribe(EventConstants.GetContentControlParameters, GetContentControlParameters);
+		}
+
+		~StubContentControlProvider()
+		{
+			Dispose(false);
+		}
 	}
 }
\ No newline at end of file