Index: Core/Common/src/Core.Common.Gui/Forms/MainWindow/MainWindow.xaml
===================================================================
diff -u -re63a6c37c6df68f5af5f7bb02b2affc6876e4bee -r8f570abee25de60fe410e7ac7566105b8fa33730
--- Core/Common/src/Core.Common.Gui/Forms/MainWindow/MainWindow.xaml	(.../MainWindow.xaml)	(revision e63a6c37c6df68f5af5f7bb02b2affc6876e4bee)
+++ Core/Common/src/Core.Common.Gui/Forms/MainWindow/MainWindow.xaml	(.../MainWindow.xaml)	(revision 8f570abee25de60fe410e7ac7566105b8fa33730)
@@ -147,7 +147,8 @@
 
             <DockPanel Height="30" DockPanel.Dock="Bottom" Style="{StaticResource PanelBackgroundWindowTitleStyle}">
                 <StackPanel Orientation="Horizontal" DockPanel.Dock="Left">
-                    <ToggleButton Style="{StaticResource ViewStateBarToggleButtonStyle}"
+                    <ToggleButton Name="ButtonShowProjectExplorer" 
+                                  Style="{StaticResource ViewStateBarToggleButtonStyle}"
                                   ToolTip="{x:Static properties:Resources.ViewStateBar_ProjectExplorer_ToolTip}"
                                   AutomationProperties.AutomationId="ViewStateButtonBarShowProjectExplorer">
                         <TextBlock Style="{StaticResource ButtonIconStyle}" Text="&#xE95B;"/>
Index: Core/Common/src/Core.Common.Gui/Forms/MainWindow/MainWindow.xaml.cs
===================================================================
diff -u -r667f6bc7aad5f7fc5b82da1b0577d92d392e91a4 -r8f570abee25de60fe410e7ac7566105b8fa33730
--- Core/Common/src/Core.Common.Gui/Forms/MainWindow/MainWindow.xaml.cs	(.../MainWindow.xaml.cs)	(revision 667f6bc7aad5f7fc5b82da1b0577d92d392e91a4)
+++ Core/Common/src/Core.Common.Gui/Forms/MainWindow/MainWindow.xaml.cs	(.../MainWindow.xaml.cs)	(revision 8f570abee25de60fe410e7ac7566105b8fa33730)
@@ -259,6 +259,7 @@
         {
             if (viewController.ViewHost != null)
             {
+                ButtonShowProjectExplorer.IsChecked = viewController.ViewHost.ToolViews.Contains(ProjectExplorer);
                 ButtonShowMessages.IsChecked = viewController.ViewHost.ToolViews.Contains(MessageWindow);
                 ButtonShowProperties.IsChecked = viewController.ViewHost.ToolViews.Contains(PropertyGrid);
             }