From d6bdd25f70695d2fa0211ce87e35095b12683e45 Mon Sep 17 00:00:00 2001
From: Bastian Schmidt <batzen@gmx.org>
Date: Mon, 11 Apr 2016 11:20:08 +0200
Subject: [PATCH] Fixes #293 by checking the container for null

---
 Changelog.md                                  |  7 ++++++-
 Fluent.Ribbon/Controls/BackstageTabControl.cs | 12 ++++++++++--
 Shared/GlobalAssemblyInfo.cs                  |  4 ++--
 appveyor.yml                                  |  4 ++--
 4 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/Changelog.md b/Changelog.md
index cf950fb3a..dc82feed0 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,6 +1,11 @@
 # Changelog for Fluent.Ribbon
 
-## 4.0.0 (preview)
+## 4.0.1
+
+- ### Bug fixes
+  - [#293](../../issues/293) - ArgumentNullException in BackstageTabControl while trying to find the selected tab
+
+## 4.0.0
 
 - ### Notices
   - **As of now the Office 2010 and Windows 8 themes will be removed in version 5.0. You can vote for this at [Future direction of this library](../../issues/282).**
diff --git a/Fluent.Ribbon/Controls/BackstageTabControl.cs b/Fluent.Ribbon/Controls/BackstageTabControl.cs
index adcfaca33..32306ae4a 100644
--- a/Fluent.Ribbon/Controls/BackstageTabControl.cs
+++ b/Fluent.Ribbon/Controls/BackstageTabControl.cs
@@ -328,14 +328,22 @@ protected override void OnSelectionChanged(SelectionChangedEventArgs e)
 
         #region Private methods
 
-        // Gets selected ribbon tab item
+        /// <summary>
+        /// Gets selected <see cref="BackstageTabItem"/>.
+        /// If there is no item selected, the first found item is selected and it's container (<see cref="BackstageTabItem"/>) is returned.
+        /// </summary>
+        /// <returns>The currently selected <see cref="BackstageTabItem"/>. Or null of nothing was selected and nothing could be selected.</returns>
         private BackstageTabItem GetSelectedTabItem()
         {
             var container = this.ItemContainerGenerator.ContainerFromItem(this.SelectedItem) as BackstageTabItem;
             if (container == null)
             {
                 container = this.FindNextTabItem(this.SelectedIndex, 1);
-                this.SelectedItem = this.ItemContainerGenerator.ItemFromContainer(container);
+
+                if (container != null)
+                {
+                    this.SelectedItem = this.ItemContainerGenerator.ItemFromContainer(container);
+                }
             }
 
             return container;
diff --git a/Shared/GlobalAssemblyInfo.cs b/Shared/GlobalAssemblyInfo.cs
index fd4901ab0..f146631ff 100644
--- a/Shared/GlobalAssemblyInfo.cs
+++ b/Shared/GlobalAssemblyInfo.cs
@@ -15,8 +15,8 @@
 [assembly: AssemblyTrademark("")]
 [assembly: AssemblyCulture("")]
 
-[assembly: AssemblyVersion("4.0.0.0")]
-[assembly: AssemblyFileVersion("4.0.0.0")]
+[assembly: AssemblyVersion("4.0.1.0")]
+[assembly: AssemblyFileVersion("4.0.1.0")]
 [assembly: AssemblyInformationalVersion("SRC")]
 
 [assembly: ComVisible(false)]
diff --git a/appveyor.yml b/appveyor.yml
index 70bfa5a90..295ef4fc4 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -6,7 +6,7 @@
     only:
       - develop
 
-  version: 4.0.0-dev{build}
+  version: 4.0.1-dev{build}
   configuration: Release
 
   init:
@@ -49,7 +49,7 @@
     only:
       - master
 
-  version: 4.0.0.{build}
+  version: 4.0.1.{build}
   configuration: Release
 
   # Install scripts. (runs after repo cloning)