Index: Core/Plugins/src/Core.Plugins.OxyPlot/OxyPlotGuiPlugin.cs
===================================================================
diff -u -rb34c0fe58a6c3228733f322c6ba0b86444397368 -rb6dea7374102ce7e7a8f13cf127ea01c36e03eb9
--- Core/Plugins/src/Core.Plugins.OxyPlot/OxyPlotGuiPlugin.cs	(.../OxyPlotGuiPlugin.cs)	(revision b34c0fe58a6c3228733f322c6ba0b86444397368)
+++ Core/Plugins/src/Core.Plugins.OxyPlot/OxyPlotGuiPlugin.cs	(.../OxyPlotGuiPlugin.cs)	(revision b6dea7374102ce7e7a8f13cf127ea01c36e03eb9)
@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Linq;
 using Core.Common.Controls.Views;
 using Core.Common.Gui;
@@ -16,6 +17,7 @@
     {
         private ChartingRibbon chartingRibbon;
         private LegendController legendController;
+        private bool activated;
 
         public override IRibbonCommandHandler RibbonCommandHandler
         {
@@ -32,6 +34,7 @@
 
             legendController.ToggleLegend();
             Gui.ActiveViewChanged += GuiOnActiveViewChanged;
+            activated = true;
         }
 
         public override IEnumerable<ViewInfo> GetViewInfoObjects()
@@ -61,7 +64,10 @@
 
         public override void Dispose()
         {
-            Gui.ActiveViewChanged -= GuiOnActiveViewChanged;
+            if (activated)
+            {
+                Gui.ActiveViewChanged -= GuiOnActiveViewChanged;
+            }
             base.Dispose();
         }
 
Index: Core/Plugins/test/Core.Plugins.OxyPlot.Test/OxyPlotGuiPluginTest.cs
===================================================================
diff -u -rb34c0fe58a6c3228733f322c6ba0b86444397368 -rb6dea7374102ce7e7a8f13cf127ea01c36e03eb9
--- Core/Plugins/test/Core.Plugins.OxyPlot.Test/OxyPlotGuiPluginTest.cs	(.../OxyPlotGuiPluginTest.cs)	(revision b34c0fe58a6c3228733f322c6ba0b86444397368)
+++ Core/Plugins/test/Core.Plugins.OxyPlot.Test/OxyPlotGuiPluginTest.cs	(.../OxyPlotGuiPluginTest.cs)	(revision b6dea7374102ce7e7a8f13cf127ea01c36e03eb9)
@@ -50,15 +50,17 @@
         public void Activate_WithGui_InitializesComponentsAndBindsActiveViewChanged()
         {
             // Setup
+            var mocks = new MockRepository();
+
             using (var plugin = new OxyPlotGuiPlugin())
             {
-                var mocks = new MockRepository();
                 var gui = mocks.StrictMock<IGui>();
                 var dockingManger = mocks.Stub<IDockingManager>();
                 var toolWindows = new ViewList(dockingManger, null);
                 var view = mocks.StrictMock<IView>();
 
                 gui.Expect(g => g.ActiveViewChanged += null).IgnoreArguments();
+                gui.Expect(g => g.ActiveViewChanged -= null).IgnoreArguments();
                 gui.Expect(g => g.ToolWindowViews).Return(toolWindows).Repeat.Twice();
                 gui.Expect(g => g.OpenToolView(Arg<LegendView>.Matches(c => true)));
                 gui.Expect(g => g.ActiveView).Return(view);
@@ -73,8 +75,8 @@
                 // Assert
                 Assert.IsInstanceOf<GuiPlugin>(plugin);
                 Assert.NotNull(plugin.RibbonCommandHandler);
-                mocks.VerifyAll();
             }
+            mocks.VerifyAll();
         }
 
         [Test]