diff --git a/src/Libraries/AvalonDock/DockableContent.cs b/src/Libraries/AvalonDock/DockableContent.cs
index c65d60ac58..5fa7d13239 100644
--- a/src/Libraries/AvalonDock/DockableContent.cs
+++ b/src/Libraries/AvalonDock/DockableContent.cs
@@ -137,7 +137,7 @@ namespace AvalonDock
         /// <summary>
         /// Dockable to a border of a <see cref="DockingManager"/> and into a <see cref="DocumentPane"/>
         /// </summary>
-        Dockable = DockableToBorders | Document,
+        Dockable = DockableToBorders | Document | Floating,
 
         /// <summary>
         /// Dockable to a border of a <see cref="DockingManager"/> and into a <see cref="DocumentPane"/> but not in autohidden mode (WinForms controls)
@@ -159,6 +159,20 @@ namespace AvalonDock
         public readonly AnchorStyle Anchor = AnchorStyle.None;
 
         public DockableContentStateAndPosition(
+           Pane containerPane,
+           int childIndex,
+           double width,
+           double height,
+           AnchorStyle anchor)
+        {
+            ContainerPane = containerPane;
+            ChildIndex = childIndex;
+            Width = width;
+            Height = height;
+            Anchor = anchor;
+        }
+
+       public DockableContentStateAndPosition(
             DockableContent cntToSave)
         {
             ContainerPane = cntToSave.ContainerPane;
@@ -485,6 +499,19 @@ namespace AvalonDock
                 storeWriter.WriteAttributeString(
                     "FloatingWindowSize", new SizeConverter().ConvertToInvariantString(FloatingWindowSize));
             }
+
+            if (SavedStateAndPosition != null)
+            {
+                storeWriter.WriteAttributeString(
+                    "ChildIndex", SavedStateAndPosition.ChildIndex.ToString());
+                storeWriter.WriteAttributeString(
+                    "Width", SavedStateAndPosition.Width.ToString());
+                storeWriter.WriteAttributeString(
+                    "Height", SavedStateAndPosition.Height.ToString());
+                storeWriter.WriteAttributeString(
+                    "Anchor", SavedStateAndPosition.Anchor.ToString());
+            }
+
         }
 
         /// <summary>
@@ -496,6 +523,28 @@ namespace AvalonDock
         {
             if (contentElement.HasAttribute("FloatingWindowSize"))
                 FloatingWindowSize = (Size)(new SizeConverter()).ConvertFromInvariantString(contentElement.GetAttribute("FloatingWindowSize"));
+
+
+            Size effectiveSize = new Size(0d, 0d);
+            if (contentElement.HasAttribute("EffectiveSize"))
+            {
+                // Store
+                effectiveSize = (Size)(new SizeConverter()).ConvertFromInvariantString(contentElement.GetAttribute("EffectiveSize"));
+            }
+
+            ResizingPanel.SetEffectiveSize(this, effectiveSize);
+
+            if (contentElement.HasAttribute("ChildIndex"))
+            {
+                _savedStateAndPosition = new DockableContentStateAndPosition(
+                    ContainerPane,
+                    int.Parse(contentElement.GetAttribute("ChildIndex")),
+                    double.Parse(contentElement.GetAttribute("Width")),
+                    double.Parse(contentElement.GetAttribute("Height")),
+                    (AnchorStyle) Enum.Parse(typeof(AnchorStyle), contentElement.GetAttribute("Anchor"))
+                    );
+
+            }
         } 
         #endregion
     }
diff --git a/src/Libraries/AvalonDock/DockingManager.cs b/src/Libraries/AvalonDock/DockingManager.cs
index dc7a0e2587..4320c6d93f 100644
--- a/src/Libraries/AvalonDock/DockingManager.cs
+++ b/src/Libraries/AvalonDock/DockingManager.cs
@@ -543,6 +543,11 @@ namespace AvalonDock
                         }
                     }
                 }
+                else
+                {
+                    _mainDocumentPane = value;
+                }
+
             }
         }
 
@@ -1746,7 +1751,11 @@ namespace AvalonDock
                 if (content.ContainerPane.GetManager() == null)
                 {
                     //disconnect the parent pane from previous panel
-                    ((Panel)content.ContainerPane.Parent).Children.Remove(content.ContainerPane);
+                    //((Panel)content.ContainerPane.Parent).Children.Remove(content.ContainerPane);
+                    if (content.ContainerPane.Parent != null)
+                    {
+                        ((Panel)content.ContainerPane.Parent).Children.Remove(content.ContainerPane);
+                    }
                     Anchor(content.ContainerPane, desideredAnchor);
                 }
 
@@ -2482,7 +2491,10 @@ namespace AvalonDock
 
         void SaveLayout(XmlWriter xmlWriter, DockableContent content)
         {
-            Debug.Assert(!string.IsNullOrEmpty(content.Name));
+            Debug.Assert(!string.IsNullOrEmpty(content.Name),
+            "DockableContent must have a Name to save its content.\n" +
+            "Click Ignore to skip this element and continue with save."
+            );
 
             if (!string.IsNullOrEmpty(content.Name))
             {
@@ -2960,6 +2972,7 @@ namespace AvalonDock
                         && hiddenContent.State != DockableContentState.Hidden)
                     {
                         Hide(hiddenContent);
+                        hiddenContent.RestoreLayout(hiddenContentElement);
                     }
                 }
             }
diff --git a/src/Libraries/AvalonDock/DocumentContent.cs b/src/Libraries/AvalonDock/DocumentContent.cs
index 75613ae0dc..07cc2682cb 100644
--- a/src/Libraries/AvalonDock/DocumentContent.cs
+++ b/src/Libraries/AvalonDock/DocumentContent.cs
@@ -158,6 +158,16 @@ namespace AvalonDock
             base.OnDragMouseLeave(sender, e);
         }
 
+        public override void OnApplyTemplate()
+        {
+            base.OnApplyTemplate();
+
+            if (DragEnabledArea != null)
+            {
+                DragEnabledArea.InputBindings.Add(new InputBinding(ApplicationCommands.Close, new MouseGesture(MouseAction.MiddleClick)));
+            }
+        }
+
         /// <summary>
         /// Event fired when the document is about to be closed
         /// </summary>
@@ -205,6 +215,7 @@ namespace AvalonDock
             }
 
 
+
             if (manager != null)
             {
                 if (manager.ActiveDocument == this)
diff --git a/src/Libraries/AvalonDock/DocumentFloatingWindow.cs b/src/Libraries/AvalonDock/DocumentFloatingWindow.cs
index 67e3c3da88..6072d9e4fd 100644
--- a/src/Libraries/AvalonDock/DocumentFloatingWindow.cs
+++ b/src/Libraries/AvalonDock/DocumentFloatingWindow.cs
@@ -348,6 +348,8 @@ namespace AvalonDock
                 DocumentContent docContent = this.HostedPane.Items[0] as DocumentContent;
                 if (!docContent.Close())
                     e.Cancel = true;
+                else
+                    this.HostedPane.Items.Remove(docContent);
             }
             
             base.OnClosing(e);
diff --git a/src/Libraries/AvalonDock/DocumentPane.cs b/src/Libraries/AvalonDock/DocumentPane.cs
index 6e35bacb4e..05644e0e2a 100644
--- a/src/Libraries/AvalonDock/DocumentPane.cs
+++ b/src/Libraries/AvalonDock/DocumentPane.cs
@@ -331,6 +331,8 @@ namespace AvalonDock
         {
             _optionsContextMenuPlacementTarget = GetTemplateChild("PART_ShowContextMenuButton") as UIElement;
 
+            
+
             base.OnApplyTemplate();
         }
 
@@ -390,14 +392,32 @@ namespace AvalonDock
 
         internal void CheckContentsEmpty()
         { 
-            if (IsMainDocumentPane.HasValue &&
-                !IsMainDocumentPane.Value &&
-                Items.Count == 0)
+            if (Items.Count == 0)
             {
-                ResizingPanel containerPanel = Parent as ResizingPanel;
-                if (containerPanel != null)
-                    containerPanel.RemoveChild(this);
-            }        
+                bool isMainDocPaneToBeClose = IsMainDocumentPane.HasValue &&
+                    IsMainDocumentPane.Value;
+
+                if (isMainDocPaneToBeClose)
+                {
+                    DockingManager manager = GetManager();
+                    DocumentPane candidateNewMainDocPane = manager.FindAnotherLogicalChildContained<DocumentPane>(this);
+                    if (candidateNewMainDocPane != null)
+                    {
+                        ResizingPanel containerPanel = Parent as ResizingPanel;
+                        if (containerPanel != null)
+                            containerPanel.RemoveChild(this);
+
+                        manager.MainDocumentPane = candidateNewMainDocPane;
+                    }
+                }
+                else
+                {
+                    ResizingPanel containerPanel = Parent as ResizingPanel;
+                    if (containerPanel != null)
+                        containerPanel.RemoveChild(this);
+                }
+            }
+
         }
 
 
diff --git a/src/Libraries/AvalonDock/HelperFunc.cs b/src/Libraries/AvalonDock/HelperFunc.cs
index 35a0be6dd5..2a6e1851fa 100644
--- a/src/Libraries/AvalonDock/HelperFunc.cs
+++ b/src/Libraries/AvalonDock/HelperFunc.cs
@@ -105,7 +105,6 @@ namespace AvalonDock
 
                 if (child is DependencyObject)
                 {
-
                     T childFound = (child as DependencyObject).GetLogicalChildContained<T>();
                     if (childFound != null)
                         return childFound;
@@ -115,6 +114,24 @@ namespace AvalonDock
             return null;
         }
 
+        public static T FindAnotherLogicalChildContained<T>(this DependencyObject obj, UIElement childToExclude) where T : DependencyObject
+        {
+            foreach (object child in LogicalTreeHelper.GetChildren(obj))
+            {
+                if (child is T && child != childToExclude)
+                    return child as T;
+
+                if (child is DependencyObject)
+                {
+                    T childFound = (child as DependencyObject).FindAnotherLogicalChildContained<T>(childToExclude);
+                    if (childFound != null)
+                        return childFound;
+                }
+            }
+
+            return null;
+        }
+
         public static DockablePane FindChildDockablePane(this DockingManager manager, AnchorStyle desideredAnchor)
         {
             foreach (UIElement childObject in LogicalTreeHelper.GetChildren(manager))
diff --git a/src/Libraries/AvalonDock/OverlayWindow.cs b/src/Libraries/AvalonDock/OverlayWindow.cs
index 907030e257..ae20f3fb55 100644
--- a/src/Libraries/AvalonDock/OverlayWindow.cs
+++ b/src/Libraries/AvalonDock/OverlayWindow.cs
@@ -201,10 +201,12 @@ namespace AvalonDock
             else
                 owdPaneInto.Enabled = !(_manager.DragPaneServices.FloatingWindow is DocumentFloatingWindow);
 
-            owdPaneBottom.Enabled = owdPaneInto.Enabled;
-            owdPaneTop.Enabled = owdPaneInto.Enabled;
-            owdPaneLeft.Enabled = owdPaneInto.Enabled;
-            owdPaneRight.Enabled = owdPaneInto.Enabled;
+            int destPaneChildCount = pane.Items.Count;
+
+            owdPaneBottom.Enabled = owdPaneInto.Enabled && destPaneChildCount > 0;
+            owdPaneTop.Enabled = owdPaneInto.Enabled && destPaneChildCount > 0;
+            owdPaneLeft.Enabled = owdPaneInto.Enabled && destPaneChildCount > 0;
+            owdPaneRight.Enabled = owdPaneInto.Enabled && destPaneChildCount > 0;
 
             CurrentDropPane = pane;
         }
diff --git a/src/Libraries/AvalonDock/Properties/AssemblyInfo.cs b/src/Libraries/AvalonDock/Properties/AssemblyInfo.cs
index 8c10c468db..fa40c104ed 100644
--- a/src/Libraries/AvalonDock/Properties/AssemblyInfo.cs
+++ b/src/Libraries/AvalonDock/Properties/AssemblyInfo.cs
@@ -59,4 +59,4 @@ using System.Runtime.InteropServices;
 //
 // You can specify all the values or you can default the Revision and Build Numbers 
 // by using the '*' as shown below:
-[assembly: AssemblyVersion("1.2.2515")]
+[assembly: AssemblyVersion("1.2.2632")]
diff --git a/src/Libraries/AvalonDock/ResizingPanel.cs b/src/Libraries/AvalonDock/ResizingPanel.cs
index d51d081ade..9a0fb64a16 100644
--- a/src/Libraries/AvalonDock/ResizingPanel.cs
+++ b/src/Libraries/AvalonDock/ResizingPanel.cs
@@ -264,6 +264,19 @@ namespace AvalonDock
                 }
                 availableSize = newAvailSize;
             }
+            //Thx to TMx
+            else if (availableSize.Height == double.PositiveInfinity &&
+                Orientation == Orientation.Vertical)
+            {
+                Size newAvailSize = new Size();
+                foreach (FrameworkElement child in visibleChildren)
+                {
+                    child.Measure(newAvailSize);
+                    newAvailSize.Width = Math.Max(child.DesiredSize.Width, newAvailSize.Width);
+                    newAvailSize.Height += child.DesiredSize.Height;
+                }
+                availableSize = newAvailSize;
+            }
 
             var splitters = from FrameworkElement child in visibleChildren
                             where child is ResizingPanelSplitter