diff --git a/src/Avalonia.Controls/ColumnDefinition.cs b/src/Avalonia.Controls/ColumnDefinition.cs
index d316881a05..8c9f6323a9 100644
--- a/src/Avalonia.Controls/ColumnDefinition.cs
+++ b/src/Avalonia.Controls/ColumnDefinition.cs
@@ -29,7 +29,7 @@ namespace Avalonia.Controls
         /// <summary>
         /// Initializes a new instance of the <see cref="ColumnDefinition"/> class.
         /// </summary>
-        public ColumnDefinition()
+        public ColumnDefinition() : base(true)
         {
         }
 
@@ -38,7 +38,7 @@ namespace Avalonia.Controls
         /// </summary>
         /// <param name="value">The width of the column.</param>
         /// <param name="type">The width unit of the column.</param>
-        public ColumnDefinition(double value, GridUnitType type)
+        public ColumnDefinition(double value, GridUnitType type): base(true)
         {
             Width = new GridLength(value, type);
         }
@@ -47,7 +47,7 @@ namespace Avalonia.Controls
         /// Initializes a new instance of the <see cref="ColumnDefinition"/> class.
         /// </summary>
         /// <param name="width">The width of the column.</param>
-        public ColumnDefinition(GridLength width)
+        public ColumnDefinition(GridLength width): base(true)
         {
             Width = width;
         }
diff --git a/src/Avalonia.Controls/DefinitionBase.cs b/src/Avalonia.Controls/DefinitionBase.cs
index e1c5979476..b25ae3ab59 100644
--- a/src/Avalonia.Controls/DefinitionBase.cs
+++ b/src/Avalonia.Controls/DefinitionBase.cs
@@ -2,6 +2,7 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System;
+using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics;
 using Avalonia.Utilities;
@@ -14,6 +15,13 @@ namespace Avalonia.Controls
     /// </summary>
     public class DefinitionBase : ContentControl
     {
+        /// <summary>
+        /// Static ctor. Used for static registration of properties.
+        /// </summary>
+        static DefinitionBase()
+        {
+            SharedSizeGroupProperty.Changed.AddClassHandler<DefinitionBase>(OnSharedSizeGroupPropertyChanged);
+        }
 
         /// <summary>
         /// Defines the <see cref="SharedSizeGroup"/> property.
@@ -57,21 +65,21 @@ namespace Avalonia.Controls
         /// </summary>
         internal void OnEnterParentTree()
         {
-            if (_sharedState == null)
-            {
-                //  start with getting SharedSizeGroup value. 
-                //  this property is NOT inhereted which should result in better overall perf.
-                string sharedSizeGroupId = SharedSizeGroup;
-                if (sharedSizeGroupId != null)
-                {
-                    SharedSizeScope privateSharedSizeScope = PrivateSharedSizeScope;
-                    if (privateSharedSizeScope != null)
-                    {
-                        _sharedState = privateSharedSizeScope.EnsureSharedState(sharedSizeGroupId);
-                        _sharedState.AddMember(this);
-                    }
-                }
-            }
+            // if (_sharedState == null)
+            // {
+            //     //  start with getting SharedSizeGroup value. 
+            //     //  this property is NOT inhereted which should result in better overall perf.
+            //     string sharedSizeGroupId = SharedSizeGroup;
+            //     if (sharedSizeGroupId != null)
+            //     {
+            //         SharedSizeScope privateSharedSizeScope = PrivateSharedSizeScope;
+            //         if (privateSharedSizeScope != null)
+            //         {
+            //             _sharedState = privateSharedSizeScope.EnsureSharedState(sharedSizeGroupId);
+            //             _sharedState.AddMember(this);
+            //         }
+            //     }
+            // }
         }
 
         /// <summary>
@@ -124,7 +132,7 @@ namespace Avalonia.Controls
         /// <remarks>
         /// This method needs to be internal to be accessable from derived classes.
         /// </remarks>
-        internal static void OnUserSizePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
+        internal static void OnUserSizePropertyChanged(AvaloniaObject d, AvaloniaPropertyChangedEventArgs e)
         {
             DefinitionBase definition = (DefinitionBase)d;
 
@@ -167,7 +175,7 @@ namespace Avalonia.Controls
         /// <remarks>
         /// This method needs to be internal to be accessable from derived classes.
         /// </remarks>
-        internal static void OnUserMinSizePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
+        internal static void OnUserMinSizePropertyChanged(AvaloniaObject d, AvaloniaPropertyChangedEventArgs e)
         {
             DefinitionBase definition = (DefinitionBase)d;
 
@@ -187,7 +195,7 @@ namespace Avalonia.Controls
         internal static bool IsUserMinSizePropertyValueValid(object value)
         {
             double v = (double)value;
-            return (!MathUtilities.IsNaN(v) && v >= 0.0d && !Double.IsPositiveInfinity(v));
+            return (!Double.IsNaN(v) && v >= 0.0d && !Double.IsPositiveInfinity(v));
         }
 
         /// <summary>
@@ -196,7 +204,7 @@ namespace Avalonia.Controls
         /// <remarks>
         /// This method needs to be internal to be accessable from derived classes.
         /// </remarks>
-        internal static void OnUserMaxSizePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
+        internal static void OnUserMaxSizePropertyChanged(AvaloniaObject d, AvaloniaPropertyChangedEventArgs e)
         {
             DefinitionBase definition = (DefinitionBase)d;
 
@@ -216,7 +224,7 @@ namespace Avalonia.Controls
         internal static bool IsUserMaxSizePropertyValueValid(object value)
         {
             double v = (double)value;
-            return (!MathUtilities.IsNaN(v) && v >= 0.0d);
+            return (!Double.IsNaN(v) && v >= 0.0d);
         }
 
         /// <summary>
@@ -230,7 +238,7 @@ namespace Avalonia.Controls
         /// elements belonging to a certain scope can easily access SharedSizeState collection. As well
         /// as been norified about enter / exit a scope.
         /// </remarks>
-        internal static void OnIsSharedSizeScopePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
+        internal static void OnIsSharedSizeScopePropertyChanged(AvaloniaObject d, AvaloniaPropertyChangedEventArgs e)
         {
             //  is it possible to optimize here something like this:
             //  if ((bool)d.GetValue(Grid.IsSharedSizeScopeProperty) == (d.GetLocalValue(PrivateSharedSizeScopeProperty) != null)
@@ -238,11 +246,11 @@ namespace Avalonia.Controls
             if ((bool)e.NewValue)
             {
                 SharedSizeScope sharedStatesCollection = new SharedSizeScope();
-                d.SetValue(PrivateSharedSizeScopeProperty, sharedStatesCollection);
+                // d.SetValue(PrivateSharedSizeScopeProperty, sharedStatesCollection);
             }
             else
             {
-                d.ClearValue(PrivateSharedSizeScopeProperty);
+                // d.ClearValue(PrivateSharedSizeScopeProperty);
             }
         }
 
@@ -307,7 +315,7 @@ namespace Avalonia.Controls
         /// <summary>
         /// Layout-time user size type.
         /// </summary>
-        internal Grid.GridLayoutTimeSizeType SizeType
+        internal Grid.LayoutTimeSizeType SizeType
         {
             get { return (_sizeType); }
             set { _sizeType = value; }
@@ -333,7 +341,7 @@ namespace Avalonia.Controls
             get
             {
                 double preferredSize = MinSize;
-                if (_sizeType != Grid.GridLayoutTimeSizeType.Auto
+                if (_sizeType != Grid.LayoutTimeSizeType.Auto
                     && preferredSize < _measureSize)
                 {
                     preferredSize = _measureSize;
@@ -477,10 +485,8 @@ namespace Avalonia.Controls
         /// <summary>
         /// <see cref="PropertyMetadata.PropertyChangedCallback"/>
         /// </summary>
-        private static void OnSharedSizeGroupPropertyChanged(AvaloniaPropertyChangedEventArgs e)
+        private static void OnSharedSizeGroupPropertyChanged(DefinitionBase definition, AvaloniaPropertyChangedEventArgs e)
         {
-            DefinitionBase definition = (DefinitionBase)e.Sender;
-
             if (definition.InParentLogicalTree)
             {
                 string sharedSizeGroupId = (string)e.NewValue;
@@ -495,14 +501,14 @@ namespace Avalonia.Controls
 
                 if ((definition._sharedState == null) && (sharedSizeGroupId != null))
                 {
-                    SharedSizeScope privateSharedSizeScope = definition.PrivateSharedSizeScope;
-                    if (privateSharedSizeScope != null)
-                    {
-                        //  if definition is not registered and both: shared size group id AND private shared scope 
-                        //  are available, then register definition.
-                        definition._sharedState = privateSharedSizeScope.EnsureSharedState(sharedSizeGroupId);
-                        definition._sharedState.AddMember(definition);
-                    }
+                    // SharedSizeScope privateSharedSizeScope = definition.PrivateSharedSizeScope;
+                    // if (privateSharedSizeScope != null)
+                    // {
+                    //     //  if definition is not registered and both: shared size group id AND private shared scope 
+                    //     //  are available, then register definition.
+                    //     definition._sharedState = privateSharedSizeScope.EnsureSharedState(sharedSizeGroupId);
+                    //     definition._sharedState.AddMember(definition);
+                    // }
                 }
             }
         }
@@ -513,12 +519,12 @@ namespace Avalonia.Controls
         /// b) contains only letters, digits and underscore ('_').
         /// c) does not start with a digit.
         /// </remarks>
-        private static bool SharedSizeGroupPropertyValueValid(string value)
+        private static string SharedSizeGroupPropertyValueValid(DefinitionBase _, string value)
         {
             //  null is default value
             if (value == null)
             {
-                return (true);
+                return value;
             }
 
             string id = (string)value;
@@ -541,11 +547,11 @@ namespace Avalonia.Controls
 
                 if (i == id.Length)
                 {
-                    return (true);
+                    return value;
                 }
             }
 
-            return (false);
+            return null;
         }
 
         /// <summary>
@@ -596,13 +602,13 @@ namespace Avalonia.Controls
 
         #region Private Properties
 
-        /// <summary>
-        /// Private getter of shared state collection dynamic property.
-        /// </summary>
-        private SharedSizeScope PrivateSharedSizeScope
-        {
-            get { return (SharedSizeScope)GetValue(PrivateSharedSizeScopeProperty); }
-        }
+        // /// <summary>
+        // /// Private getter of shared state collection dynamic property.
+        // /// </summary>
+        // private SharedSizeScope PrivateSharedSizeScope
+        // {
+        //     get { return (SharedSizeScope)GetValue(PrivateSharedSizeScopeProperty); }
+        // }
 
         /// <summary>
         /// Convenience accessor to UseSharedMinimum flag
@@ -635,7 +641,7 @@ namespace Avalonia.Controls
         private Flags _flags;                           //  flags reflecting various aspects of internal state
         private int _parentIndex;                       //  this instance's index in parent's children collection
 
-        private Grid.GridLayoutTimeSizeType _sizeType;      //  layout-time user size type. it may differ from _userSizeValueCache.UnitType when calculating "to-content"
+        private Grid.LayoutTimeSizeType _sizeType;      //  layout-time user size type. it may differ from _userSizeValueCache.UnitType when calculating "to-content"
 
         private double _minSize;                        //  used during measure to accumulate size for "Auto" and "Star" DefinitionBase's
         private double _measureSize;                    //  size, calculated to be the input contstraint size for Child.Measure
@@ -716,7 +722,7 @@ namespace Avalonia.Controls
                 _sharedSizeScope = sharedSizeScope;
                 _sharedSizeGroupId = sharedSizeGroupId;
                 _registry = new List<DefinitionBase>();
-                _layoutUpdated = new EventHandler(OnLayoutUpdated);
+                // _layoutUpdated = new EventHandler(OnLayoutUpdated);
                 _broadcastInvalidation = true;
             }
 
@@ -775,7 +781,8 @@ namespace Avalonia.Controls
                 if (_layoutUpdatedHost == null)
                 {
                     _layoutUpdatedHost = layoutUpdatedHost;
-                    _layoutUpdatedHost.LayoutUpdated += _layoutUpdated;
+                    // PORTING HACK... Remove this when resolved.
+                    _layoutUpdatedHost.GetSubject(Visual.BoundsProperty).Subscribe(p => _layoutUpdated?.Invoke(this, null));
                 }
             }
 
@@ -884,7 +891,7 @@ namespace Avalonia.Controls
 
                 _minSize = sharedMinSize;
 
-                _layoutUpdatedHost.LayoutUpdated -= _layoutUpdated;
+                // _layoutUpdatedHost.LayoutUpdated -= _layoutUpdated;
                 _layoutUpdatedHost = null;
 
                 _broadcastInvalidation = true;
@@ -902,14 +909,6 @@ namespace Avalonia.Controls
         }
 
 
-        /// <summary>
-        /// Static ctor. Used for static registration of properties.
-        /// </summary>
-        static DefinitionBase()
-        {
-            SharedSizeGroupProperty.Changed.AddClassHandler<DefinitionBase>(OnSharedSizeGroupPropertyChanged);
-        }
-
         #endregion Properties
     }
 }
diff --git a/src/Avalonia.Controls/GridWPF.cs b/src/Avalonia.Controls/GridWPF.cs
index d42d6fc651..c9397e2e20 100644
--- a/src/Avalonia.Controls/GridWPF.cs
+++ b/src/Avalonia.Controls/GridWPF.cs
@@ -84,6 +84,98 @@ namespace Avalonia.Controls
             set { SetValue(ShowGridLinesProperty, value); }
         }
 
+
+        /// <summary>
+        /// Gets the value of the Column attached property for a control.
+        /// </summary>
+        /// <param name="element">The control.</param>
+        /// <returns>The control's column.</returns>
+        public static int GetColumn(AvaloniaObject element)
+        {
+            return element.GetValue(ColumnProperty);
+        }
+
+        /// <summary>
+        /// Gets the value of the ColumnSpan attached property for a control.
+        /// </summary>
+        /// <param name="element">The control.</param>
+        /// <returns>The control's column span.</returns>
+        public static int GetColumnSpan(AvaloniaObject element)
+        {
+            return element.GetValue(ColumnSpanProperty);
+        }
+
+        /// <summary>
+        /// Gets the value of the Row attached property for a control.
+        /// </summary>
+        /// <param name="element">The control.</param>
+        /// <returns>The control's row.</returns>
+        public static int GetRow(AvaloniaObject element)
+        {
+            return element.GetValue(RowProperty);
+        }
+
+        /// <summary>
+        /// Gets the value of the RowSpan attached property for a control.
+        /// </summary>
+        /// <param name="element">The control.</param>
+        /// <returns>The control's row span.</returns>
+        public static int GetRowSpan(AvaloniaObject element)
+        {
+            return element.GetValue(RowSpanProperty);
+        }
+
+
+        /// <summary>
+        /// Gets the value of the IsSharedSizeScope attached property for a control.
+        /// </summary>
+        /// <param name="element">The control.</param>
+        /// <returns>The control's IsSharedSizeScope value.</returns>
+        public static bool GetIsSharedSizeScope(AvaloniaObject element)
+        {
+            return element.GetValue(IsSharedSizeScopeProperty);
+        }
+
+        /// <summary>
+        /// Sets the value of the Column attached property for a control.
+        /// </summary>
+        /// <param name="element">The control.</param>
+        /// <param name="value">The column value.</param>
+        public static void SetColumn(AvaloniaObject element, int value)
+        {
+            element.SetValue(ColumnProperty, value);
+        }
+
+        /// <summary>
+        /// Sets the value of the ColumnSpan attached property for a control.
+        /// </summary>
+        /// <param name="element">The control.</param>
+        /// <param name="value">The column span value.</param>
+        public static void SetColumnSpan(AvaloniaObject element, int value)
+        {
+            element.SetValue(ColumnSpanProperty, value);
+        }
+
+        /// <summary>
+        /// Sets the value of the Row attached property for a control.
+        /// </summary>
+        /// <param name="element">The control.</param>
+        /// <param name="value">The row value.</param>
+        public static void SetRow(AvaloniaObject element, int value)
+        {
+            element.SetValue(RowProperty, value);
+        }
+
+        /// <summary>
+        /// Sets the value of the RowSpan attached property for a control.
+        /// </summary>
+        /// <param name="element">The control.</param>
+        /// <param name="value">The row span value.</param>
+        public static void SetRowSpan(AvaloniaObject element, int value)
+        {
+            element.SetValue(RowSpanProperty, value);
+        }
+
         private ColumnDefinitions _columnDefinitions;
         private RowDefinitions _rowDefinitions;
 
@@ -484,12 +576,11 @@ namespace Avalonia.Controls
 
             for (int i = PrivateCells.Length - 1; i >= 0; --i)
             {
-                var child = Children[i];
+                var child = Children[i] as Control;
                 if (child == null)
                 {
                     continue;
                 }
-
                 CellCache cell = new CellCache();
 
                 //
@@ -499,20 +590,20 @@ namespace Avalonia.Controls
                 //  read indices from the corresponding properties
                 //      clamp to value < number_of_columns
                 //      column >= 0 is guaranteed by property value validation callback
-                cell.ColumnIndex = Math.Min(child.GetValue(Grid.ColumnProperty), DefinitionsU.Length - 1);
+                cell.ColumnIndex = Math.Min(GetColumn(child), DefinitionsU.Length - 1);
                 //      clamp to value < number_of_rows
                 //      row >= 0 is guaranteed by property value validation callback
-                cell.RowIndex = Math.Min(child.GetValue(Grid.RowProperty), DefinitionsV.Length - 1);
+                cell.RowIndex = Math.Min(GetRow(child), DefinitionsV.Length - 1);
 
                 //  read span properties
                 //      clamp to not exceed beyond right side of the grid
                 //      column_span > 0 is guaranteed by property value validation callback
-                cell.ColumnSpan = Math.Min(child.GetValue(Grid.ColumnSpanProperty), DefinitionsU.Length - cell.ColumnIndex);
+                cell.ColumnSpan = Math.Min(GetColumnSpan(child), DefinitionsU.Length - cell.ColumnIndex);
 
                 //      clamp to not exceed beyond bottom side of the grid
                 //      row_span > 0 is guaranteed by property value validation callback
-                cell.RowSpan = Math.Min(child.GetValue(Grid.RowSpanProperty), DefinitionsV.Length - cell.RowIndex);
-
+                cell.RowSpan = Math.Min(GetRowSpan(child), DefinitionsV.Length - cell.RowIndex);
+                
                 Debug.Assert(0 <= cell.ColumnIndex && cell.ColumnIndex < DefinitionsU.Length);
                 Debug.Assert(0 <= cell.RowIndex && cell.RowIndex < DefinitionsV.Length);
 
diff --git a/src/Avalonia.Controls/RowDefinition.cs b/src/Avalonia.Controls/RowDefinition.cs
index 7307843417..d42ffdfc28 100644
--- a/src/Avalonia.Controls/RowDefinition.cs
+++ b/src/Avalonia.Controls/RowDefinition.cs
@@ -29,7 +29,7 @@ namespace Avalonia.Controls
         /// <summary>
         /// Initializes a new instance of the <see cref="RowDefinition"/> class.
         /// </summary>
-        public RowDefinition()
+        public RowDefinition() : base(false)
         {
         }
 
@@ -38,7 +38,7 @@ namespace Avalonia.Controls
         /// </summary>
         /// <param name="value">The height of the row.</param>
         /// <param name="type">The height unit of the column.</param>
-        public RowDefinition(double value, GridUnitType type)
+        public RowDefinition(double value, GridUnitType type): base(false)
         {
             Height = new GridLength(value, type);
         }
@@ -47,7 +47,7 @@ namespace Avalonia.Controls
         /// Initializes a new instance of the <see cref="RowDefinition"/> class.
         /// </summary>
         /// <param name="height">The height of the column.</param>
-        public RowDefinition(GridLength height)
+        public RowDefinition(GridLength height): base(false)
         {
             Height = height;
         }
diff --git a/src/Avalonia.Controls/Utils/SharedSizeScopeHost.cs b/src/Avalonia.Controls/Utils/SharedSizeScopeHost.cs
index 8553165e4b..5f70557385 100644
--- a/src/Avalonia.Controls/Utils/SharedSizeScopeHost.cs
+++ b/src/Avalonia.Controls/Utils/SharedSizeScopeHost.cs
@@ -395,8 +395,8 @@ namespace Avalonia.Controls
         /// </summary>
         public void Dispose()
         {
-            while (_measurementCaches.Any())
-                _measurementCaches[0].Grid.SharedScopeChanged();
+            // while (_measurementCaches.Any())
+            //     _measurementCaches[0].Grid.SharedScopeChanged();
         }
 
         /// <summary>