Index: Core/Gui/src/Core.Gui/Forms/Main/MainWindow.xaml.cs
===================================================================
diff -u -r747fccb3885c38bfce3564c54d65c63befd4eaf4 -re093037094e59f25c0877167cd63287baf2f8409
--- Core/Gui/src/Core.Gui/Forms/Main/MainWindow.xaml.cs	(.../MainWindow.xaml.cs)	(revision 747fccb3885c38bfce3564c54d65c63befd4eaf4)
+++ Core/Gui/src/Core.Gui/Forms/Main/MainWindow.xaml.cs	(.../MainWindow.xaml.cs)	(revision e093037094e59f25c0877167cd63287baf2f8409)
@@ -238,6 +238,8 @@
             InitChartLegendWindow();
             InitMessagesWindow();
             InitPropertiesWindowOrBringToFront();
+
+            UpdateToolWindowButtonState();
         }
 
         public void ValidateItems()