diff --git a/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Controls/ControlStyles.xaml b/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Controls/ControlStyles.xaml
index fb697b8d79..7d24fe7cef 100644
--- a/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Controls/ControlStyles.xaml
+++ b/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Controls/ControlStyles.xaml
@@ -27,6 +27,16 @@
 		</Setter>
 	</Style>
 	
+	<Style TargetType="{x:Type src:DragFrame}">
+		<Setter Property="Template">
+			<Setter.Value>
+				<ControlTemplate TargetType="{x:Type src:DragFrame}">
+					<Rectangle Fill="#519ABFE5" Stroke="#FF7A8787" StrokeThickness="1"/>
+				</ControlTemplate>
+			</Setter.Value>
+		</Setter>
+	</Style>
+	
 	<Style TargetType="{x:Type src:ContainerDragHandle}">
 		<Setter Property="Template">
 			<Setter.Value>
diff --git a/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Controls/DragFrame.cs b/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Controls/DragFrame.cs
new file mode 100644
index 0000000000..92f7b441fc
--- /dev/null
+++ b/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Controls/DragFrame.cs
@@ -0,0 +1,32 @@
+// <file>
+//     <copyright see="prj:///doc/copyright.txt"/>
+//     <license see="prj:///doc/license.txt"/>
+//     <owner name="Daniel Grunwald" email="daniel@danielgrunwald.de"/>
+//     <version>$Revision$</version>
+// </file>
+
+using System;
+using System.ComponentModel;
+using System.Diagnostics;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Input;
+using System.Windows.Media;
+
+using ICSharpCode.WpfDesign.Extensions;
+
+namespace ICSharpCode.WpfDesign.Designer.Controls
+{
+	/// <summary>
+	/// The rectangle shown during a drag'n'drop operation.
+	/// </summary>
+	public class DragFrame : Control
+	{
+		static DragFrame()
+		{
+			//This OverrideMetadata call tells the system that this element wants to provide a style that is different than its base class.
+			//This style is defined in themes\generic.xaml
+			DefaultStyleKeyProperty.OverrideMetadata(typeof(DragFrame), new FrameworkPropertyMetadata(typeof(DragFrame)));
+		}
+	}
+}
diff --git a/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Extensions/DefaultChildResizeSupport.cs b/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Extensions/DefaultChildResizeSupport.cs
new file mode 100644
index 0000000000..e8a9bfdb72
--- /dev/null
+++ b/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Extensions/DefaultChildResizeSupport.cs
@@ -0,0 +1,169 @@
+// <file>
+//     <copyright see="prj:///doc/copyright.txt"/>
+//     <license see="prj:///doc/license.txt"/>
+//     <owner name="Daniel Grunwald" email="daniel@danielgrunwald.de"/>
+//     <version>$Revision$</version>
+// </file>
+
+using System;
+using ICSharpCode.WpfDesign.Extensions;
+using ICSharpCode.WpfDesign.Adorners;
+using System.Windows;
+
+namespace ICSharpCode.WpfDesign.Designer.Extensions
+{
+	/// <summary>
+	/// Implements IChildResizeSupport supporting size changes using the
+	/// Width, Height, Margin properties.
+	/// </summary>
+	//[ExtensionFor(typeof(FrameworkElement))]
+	sealed class DefaultChildResizeSupport : IChildResizeSupport
+	{
+		// the default behavior is not an extension because it does not depend
+		// on a parent container instance
+		public static readonly DefaultChildResizeSupport Instance = new DefaultChildResizeSupport();
+		
+		/*
+		/// <inherits/>
+		protected override void OnInitialized()
+		{
+			base.OnInitialized();
+			this.ExtendedItem.AddBehavior(typeof(IChildResizeSupport), this);
+		}
+		 */
+		
+		/// <inherits/>
+		public bool CanResizeChild(DesignItem childItem)
+		{
+			FrameworkElement child = (FrameworkElement)childItem.Component;
+			return !double.IsNaN(child.Width)
+				|| !double.IsNaN(child.Height)
+				|| childItem.Properties[FrameworkElement.MarginProperty].IsSet;
+		}
+		
+		/// <inherits/>
+		public Placement GetPlacement(DesignItem childItem, double horizontalChange, double verticalChange, HorizontalAlignment horizontal, VerticalAlignment vertical)
+		{
+			FrameworkElement child = (FrameworkElement)childItem.Component;
+			if (childItem.Properties[FrameworkElement.MarginProperty].IsSet == false) {
+				if (child.HorizontalAlignment == HorizontalAlignment.Left)
+					horizontal = HorizontalAlignment.Right;
+				else if (child.HorizontalAlignment == HorizontalAlignment.Right)
+					horizontal = HorizontalAlignment.Left;
+				else
+					horizontal = HorizontalAlignment.Center;
+				if (child.VerticalAlignment == VerticalAlignment.Top)
+					horizontal = HorizontalAlignment.Right;
+				else if (child.VerticalAlignment == VerticalAlignment.Bottom)
+					vertical = VerticalAlignment.Bottom;
+				else
+					vertical = VerticalAlignment.Center;
+			}
+			return RootElementResizeSupport.Instance.GetPlacement(childItem, horizontalChange, verticalChange, horizontal, vertical);
+		}
+		
+		/// <inherits/>
+		public void Resize(DesignItem childItem, double horizontalChange, double verticalChange, HorizontalAlignment horizontal, VerticalAlignment vertical)
+		{
+			RelativePlacement p = (RelativePlacement)GetPlacement(childItem, horizontalChange, verticalChange, horizontal, vertical);
+			Resize(childItem, p, horizontalChange, verticalChange, horizontal, vertical);
+		}
+		
+		static void Resize(DesignItem childItem, RelativePlacement p, double horizontalChange, double verticalChange, HorizontalAlignment horizontal, VerticalAlignment vertical)
+		{
+			DesignItemProperty margin = childItem.Properties[FrameworkElement.MarginProperty];
+			if (margin.IsSet) {
+				Thickness t = (Thickness)margin.ValueOnInstance;
+				t.Left += p.XOffset;
+				t.Top += p.YOffset;
+				t.Right -= p.XOffset + p.WidthOffset;
+				t.Bottom -= p.YOffset + p.HeightOffset;
+				margin.SetValue(t);
+			}
+			
+			FrameworkElement child = (FrameworkElement)childItem.Component;
+			double width = child.Width;
+			double height = child.Height;
+			if (margin.IsSet) {
+				// when margin is used, only set width/height if it is not Auto
+				if (!double.IsNaN(width)) {
+					childItem.Properties[FrameworkElement.WidthProperty].SetValue( Math.Max(0, horizontalChange + width) );
+				}
+				if (!double.IsNaN(height)) {
+					childItem.Properties[FrameworkElement.HeightProperty].SetValue( Math.Max(0, verticalChange + height) );
+				}
+			} else {
+				// when margin is not used, we'll have to set width+height
+				// but don't create width if we don't have any horizontal change
+				if (double.IsNaN(width) && horizontalChange != 0) {
+					width = child.ActualWidth;
+				}
+				if (double.IsNaN(height) && verticalChange != 0) {
+					height = child.ActualHeight;
+				}
+				if (!double.IsNaN(width)) {
+					childItem.Properties[FrameworkElement.WidthProperty].SetValue( Math.Max(0, horizontalChange + width) );
+				}
+				if (!double.IsNaN(height)) {
+					childItem.Properties[FrameworkElement.HeightProperty].SetValue( Math.Max(0, verticalChange + height) );
+				}
+			}
+		}
+	}
+	
+	sealed class RootElementResizeSupport : IChildResizeSupport
+	{
+		public static readonly RootElementResizeSupport Instance = new RootElementResizeSupport();
+		
+		public bool CanResizeChild(DesignItem child)
+		{
+			return true;
+		}
+		
+		public Placement GetPlacement(DesignItem child, double horizontalChange, double verticalChange, HorizontalAlignment horizontal, VerticalAlignment vertical)
+		{
+			RelativePlacement rp = new RelativePlacement(HorizontalAlignment.Stretch, VerticalAlignment.Stretch);
+			
+			if (horizontal == HorizontalAlignment.Right) {
+				rp.WidthOffset += horizontalChange;
+			} else if (horizontal == HorizontalAlignment.Left) {
+				rp.XOffset -= horizontalChange;
+				rp.WidthOffset += horizontalChange;
+			} else {
+				rp.XOffset -= horizontalChange / 2;
+				rp.WidthOffset += horizontalChange;
+			}
+			
+			if (vertical == VerticalAlignment.Bottom) {
+				rp.HeightOffset += verticalChange;
+			} else if (vertical == VerticalAlignment.Top) {
+				rp.YOffset -= verticalChange;
+				rp.HeightOffset += verticalChange;
+			} else {
+				rp.YOffset -= verticalChange / 2;
+				rp.HeightOffset += verticalChange;
+			}
+			
+			return rp;
+		}
+		
+		public void Resize(DesignItem childItem, double horizontalChange, double verticalChange, HorizontalAlignment horizontal, VerticalAlignment vertical)
+		{
+			FrameworkElement child = (FrameworkElement)childItem.Component;
+			double width = child.Width;
+			double height = child.Height;
+			if (double.IsNaN(width) && horizontalChange != 0) {
+				width = child.ActualWidth;
+			}
+			if (double.IsNaN(height) && verticalChange != 0) {
+				height = child.ActualHeight;
+			}
+			if (!double.IsNaN(width)) {
+				childItem.Properties[FrameworkElement.WidthProperty].SetValue( Math.Max(0, horizontalChange + width) );
+			}
+			if (!double.IsNaN(height)) {
+				childItem.Properties[FrameworkElement.HeightProperty].SetValue( Math.Max(0, verticalChange + height) );
+			}
+		}
+	}
+}
diff --git a/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Extensions/ResizeThumbExtension.cs b/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Extensions/ResizeThumbExtension.cs
new file mode 100644
index 0000000000..1e85071f9f
--- /dev/null
+++ b/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Extensions/ResizeThumbExtension.cs
@@ -0,0 +1,167 @@
+// <file>
+//     <copyright see="prj:///doc/copyright.txt"/>
+//     <license see="prj:///doc/license.txt"/>
+//     <owner name="Daniel Grunwald" email="daniel@danielgrunwald.de"/>
+//     <version>$Revision$</version>
+// </file>
+
+using System;
+using System.Collections.Generic;
+using System.Windows;
+using System.Windows.Input;
+using System.Windows.Controls;
+using System.Windows.Controls.Primitives;
+using ICSharpCode.WpfDesign.Adorners;
+using ICSharpCode.WpfDesign.Extensions;
+using ICSharpCode.WpfDesign.Designer.Controls;
+
+namespace ICSharpCode.WpfDesign.Designer.Extensions
+{
+	/// <summary>
+	/// The resize thumb at the top left edge of a component.
+	/// </summary>
+	[ExtensionFor(typeof(FrameworkElement))]
+	public sealed class ResizeThumbExtension : PrimarySelectionAdornerProvider
+	{
+		AdornerPanel adornerPanel;
+		DragFrame dragFrame;
+		
+		/// <summary></summary>
+		public ResizeThumbExtension()
+		{
+			adornerPanel = new AdornerPanel();
+			adornerPanel.Order = AdornerOrder.Foreground;
+			
+			CreateThumb(HorizontalAlignment.Left, VerticalAlignment.Top);
+			CreateThumb(HorizontalAlignment.Right, VerticalAlignment.Top);
+			CreateThumb(HorizontalAlignment.Left, VerticalAlignment.Bottom);
+			CreateThumb(HorizontalAlignment.Right, VerticalAlignment.Bottom);
+		}
+		
+		void CreateThumb(HorizontalAlignment horizontalAlignment, VerticalAlignment verticalAlignment)
+		{
+			ResizeThumb resizeThumb = new ResizeThumb();
+			AdornerPanel.SetPlacement(resizeThumb, new RelativePlacement(horizontalAlignment, verticalAlignment));
+			adornerPanel.Children.Add(resizeThumb);
+			
+			resizeThumb.DragStarted   += OnDragStarted;
+			resizeThumb.DragDelta     += OnDragDelta(horizontalAlignment, verticalAlignment);
+			resizeThumb.DragCompleted += OnDragCompleted(horizontalAlignment, verticalAlignment);
+		}
+		
+		IChildResizeSupport resizeBehavior;
+		
+		void OnDragStarted(object sender, DragStartedEventArgs e)
+		{
+			if (dragFrame == null)
+				dragFrame = new DragFrame();
+			
+			AdornerPanel.SetPlacement(dragFrame, Placement.FillContent);
+			adornerPanel.Children.Add(dragFrame);
+			adornerPanel.Cursor = Cursors.SizeNWSE;
+//			newSize.Width = double.IsNaN(component.Width) ? component.ActualWidth : component.Width;
+//			newSize.Height = double.IsNaN(component.Height) ? component.ActualHeight : component.Height;
+		}
+		
+		DragDeltaEventHandler OnDragDelta(HorizontalAlignment horizontalAlignment, VerticalAlignment verticalAlignment)
+		{
+			return delegate(object sender, DragDeltaEventArgs e) {
+				if (resizeBehavior != null) {
+					Placement p = resizeBehavior.GetPlacement(this.ExtendedItem,
+					                                          FixChange(e.HorizontalChange, horizontalAlignment),
+					                                          FixChange(e.VerticalChange, verticalAlignment),
+					                                          horizontalAlignment, verticalAlignment);
+					if (p != null) {
+						AdornerPanel.SetPlacement(dragFrame, p);
+					}
+				}
+			};
+		}
+		
+		DragCompletedEventHandler OnDragCompleted(HorizontalAlignment horizontalAlignment, VerticalAlignment verticalAlignment)
+		{
+			return delegate (object sender, DragCompletedEventArgs e) {
+				adornerPanel.Children.Remove(dragFrame);
+				adornerPanel.ClearValue(AdornerPanel.CursorProperty);
+				
+				if (resizeBehavior != null) {
+					resizeBehavior.Resize(this.ExtendedItem,
+					                      FixChange(e.HorizontalChange, horizontalAlignment),
+					                      FixChange(e.VerticalChange, verticalAlignment),
+					                      horizontalAlignment, verticalAlignment);
+				}
+			};
+		}
+		
+		double FixChange(double val, VerticalAlignment va)
+		{
+			if (va == VerticalAlignment.Bottom)
+				return val;
+			else if (va == VerticalAlignment.Top)
+				return -val;
+			else
+				return 0;
+		}
+		
+		double FixChange(double val, HorizontalAlignment ha)
+		{
+			if (ha == HorizontalAlignment.Right)
+				return val;
+			else if (ha == HorizontalAlignment.Left)
+				return -val;
+			else
+				return 0;
+		}
+		
+		/// <summary/>
+		protected override void OnInitialized()
+		{
+			base.OnInitialized();
+			this.ExtendedItem.PropertyChanged += OnPropertyChanged;
+			this.Services.Selection.PrimarySelectionChanged += OnPrimarySelectionChanged;
+			
+			DesignItem parentItem = this.ExtendedItem.Parent;
+			if (parentItem == null) // resizing the root element
+				resizeBehavior = RootElementResizeSupport.Instance;
+			else
+				resizeBehavior = parentItem.GetBehavior<IChildResizeSupport>() ?? DefaultChildResizeSupport.Instance;
+			
+			UpdateAdornerVisibility();
+			OnPrimarySelectionChanged(null, null);
+		}
+		
+		void OnPropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
+		{
+			UpdateAdornerVisibility();
+		}
+		
+		/// <summary/>
+		protected override void OnRemove()
+		{
+			this.ExtendedItem.PropertyChanged -= OnPropertyChanged;
+			this.Services.Selection.PrimarySelectionChanged -= OnPrimarySelectionChanged;
+			base.OnRemove();
+		}
+		
+		void OnPrimarySelectionChanged(object sender, EventArgs e)
+		{
+			bool isPrimarySelection = this.Services.Selection.PrimarySelection == this.ExtendedItem;
+			foreach (ResizeThumb g in adornerPanel.Children) {
+				g.IsPrimarySelection = isPrimarySelection;
+			}
+		}
+		
+		void UpdateAdornerVisibility()
+		{
+			if (resizeBehavior == null || !resizeBehavior.CanResizeChild(this.ExtendedItem)) {
+				if (this.Adorners.Count == 1) {
+					this.Adorners.Clear();
+				}
+			} else {
+				if (this.Adorners.Count == 0) {
+					this.Adorners.Add(adornerPanel);
+				}
+			}
+		}
+	}
+}
diff --git a/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Extensions/TopLeftGrabHandle.cs b/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Extensions/TopLeftGrabHandle.cs
deleted file mode 100644
index 50f2dd5c77..0000000000
--- a/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Extensions/TopLeftGrabHandle.cs
+++ /dev/null
@@ -1,99 +0,0 @@
-// <file>
-//     <copyright see="prj:///doc/copyright.txt"/>
-//     <license see="prj:///doc/license.txt"/>
-//     <owner name="Daniel Grunwald" email="daniel@danielgrunwald.de"/>
-//     <version>$Revision$</version>
-// </file>
-
-using System;
-using System.Collections.Generic;
-using System.Windows;
-using System.Windows.Controls;
-using System.Windows.Controls.Primitives;
-using ICSharpCode.WpfDesign.Adorners;
-using ICSharpCode.WpfDesign.Extensions;
-using ICSharpCode.WpfDesign.Designer.Controls;
-
-namespace ICSharpCode.WpfDesign.Designer.Extensions
-{
-	/// <summary>
-	/// The resize thumb at the top left edge of a component.
-	/// </summary>
-	[ExtensionFor(typeof(FrameworkElement))]
-	public sealed class TopLeftResizeThumb : PrimarySelectionAdornerProvider
-	{
-		AdornerPanel adornerPanel;
-		
-		/// <summary></summary>
-		public TopLeftResizeThumb()
-		{
-			adornerPanel = new AdornerPanel();
-			adornerPanel.Order = AdornerOrder.Foreground;
-			
-			ResizeThumb resizeThumb;
-			
-			resizeThumb = new ResizeThumb();
-			AdornerPanel.SetPlacement(resizeThumb, new RelativePlacement(HorizontalAlignment.Left, VerticalAlignment.Top));
-			adornerPanel.Children.Add(resizeThumb);
-			
-			resizeThumb = new ResizeThumb();
-			AdornerPanel.SetPlacement(resizeThumb, new RelativePlacement(HorizontalAlignment.Right, VerticalAlignment.Top));
-			adornerPanel.Children.Add(resizeThumb);
-			
-			resizeThumb = new ResizeThumb();
-			AdornerPanel.SetPlacement(resizeThumb, new RelativePlacement(HorizontalAlignment.Left, VerticalAlignment.Bottom));
-			adornerPanel.Children.Add(resizeThumb);
-			
-			resizeThumb = new ResizeThumb();
-			AdornerPanel.SetPlacement(resizeThumb, new RelativePlacement(HorizontalAlignment.Right, VerticalAlignment.Bottom));
-			adornerPanel.Children.Add(resizeThumb);
-		}
-		
-		/// <summary/>
-		protected override void OnInitialized()
-		{
-			base.OnInitialized();
-			this.ExtendedItem.PropertyChanged += OnPropertyChanged;
-			this.Services.Selection.PrimarySelectionChanged += OnPrimarySelectionChanged;
-			UpdateAdornerVisibility();
-			OnPrimarySelectionChanged(null, null);
-		}
-		
-		/// <summary/>
-		protected override void OnRemove()
-		{
-			this.ExtendedItem.PropertyChanged -= OnPropertyChanged;
-			this.Services.Selection.PrimarySelectionChanged -= OnPrimarySelectionChanged;
-			base.OnRemove();
-		}
-		
-		void OnPropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
-		{
-			if (e.PropertyName == "Width" || e.PropertyName == "Height") {
-				UpdateAdornerVisibility();
-			}
-		}
-		
-		void OnPrimarySelectionChanged(object sender, EventArgs e)
-		{
-			bool isPrimarySelection = this.Services.Selection.PrimarySelection == this.ExtendedItem;
-			foreach (ResizeThumb g in adornerPanel.Children) {
-				g.IsPrimarySelection = isPrimarySelection;
-			}
-		}
-		
-		void UpdateAdornerVisibility()
-		{
-			FrameworkElement element = (FrameworkElement)this.ExtendedItem.Component;
-			if (double.IsNaN(element.Width) && double.IsNaN(element.Height)) {
-				if (this.Adorners.Count == 1) {
-					this.Adorners.Clear();
-				}
-			} else {
-				if (this.Adorners.Count == 0) {
-					this.Adorners.Add(adornerPanel);
-				}
-			}
-		}
-	}
-}
diff --git a/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/WpfDesign.Designer.csproj b/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/WpfDesign.Designer.csproj
index de675fb9fa..49f3d14693 100644
--- a/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/WpfDesign.Designer.csproj
+++ b/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/WpfDesign.Designer.csproj
@@ -58,6 +58,7 @@
     <Compile Include="Configuration\AssemblyInfo.cs" />
     <Compile Include="Controls\AdornerLayer.cs" />
     <Compile Include="Controls\ContainerDragHandle.cs" />
+    <Compile Include="Controls\DragFrame.cs" />
     <Compile Include="Controls\ErrorBalloon.cs" />
     <Compile Include="Controls\PropertyEditor\DependencyPropertyDotButton.cs" />
     <Compile Include="Controls\PropertyEditor\PropertyEditor.cs" />
@@ -69,11 +70,12 @@
     <Compile Include="Controls\TypeEditors\BrushEditor.cs" />
     <Compile Include="Controls\WindowClone.cs" />
     <Compile Include="DesignPanel.cs" />
+    <Compile Include="Extensions\DefaultChildResizeSupport.cs" />
     <Compile Include="Extensions\PanelInstanceFactory.cs" />
     <Compile Include="Extensions\SelectedElementRectangleExtension.cs" />
     <Compile Include="Extensions\TabItemClickableExtension.cs" />
     <Compile Include="Extensions\TopLeftContainerDragHandle.cs" />
-    <Compile Include="Extensions\TopLeftGrabHandle.cs" />
+    <Compile Include="Extensions\ResizeThumbExtension.cs" />
     <Compile Include="Linq.cs" />
     <Compile Include="ServiceRequiredException.cs" />
     <Compile Include="Services\ErrorService.cs" />
diff --git a/src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/Adorners/Placement.cs b/src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/Adorners/Placement.cs
index 489a52e7ae..4715284ae3 100644
--- a/src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/Adorners/Placement.cs
+++ b/src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/Adorners/Placement.cs
@@ -152,12 +152,12 @@ namespace ICSharpCode.WpfDesign.Adorners
 		
 		Size CalculateSize(UIElement adorner, Size adornedElementSize)
 		{
-			return new Size(widthOffset
-			                + widthRelativeToDesiredWidth * adorner.DesiredSize.Width
-			                + widthRelativeToContentWidth * adornedElementSize.Width,
-			                heightOffset
-			                + heightRelativeToDesiredHeight * adorner.DesiredSize.Height
-			                + heightRelativeToContentHeight * adornedElementSize.Height);
+			return new Size(Math.Max(widthOffset
+			                         + widthRelativeToDesiredWidth * adorner.DesiredSize.Width
+			                         + widthRelativeToContentWidth * adornedElementSize.Width, 0),
+			                Math.Max(heightOffset
+			                         + heightRelativeToDesiredHeight * adorner.DesiredSize.Height
+			                         + heightRelativeToContentHeight * adornedElementSize.Height, 0));
 		}
 		
 		double xOffset, yOffset;
diff --git a/src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/Behavior.cs b/src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/Behavior.cs
new file mode 100644
index 0000000000..60179c73bd
--- /dev/null
+++ b/src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/Behavior.cs
@@ -0,0 +1,47 @@
+// <file>
+//     <copyright see="prj:///doc/copyright.txt"/>
+//     <license see="prj:///doc/license.txt"/>
+//     <owner name="Daniel Grunwald" email="daniel@danielgrunwald.de"/>
+//     <version>$Revision$</version>
+// </file>
+
+using System;
+using ICSharpCode.WpfDesign.Adorners;
+using System.Windows;
+
+namespace ICSharpCode.WpfDesign
+{
+	/// <summary>
+	/// Behavior interface implemented by container elements to support resizing
+	/// child elements.
+	/// </summary>
+	public interface IChildResizeSupport
+	{
+		/// <summary>
+		/// Gets if the child element can be resized.
+		/// </summary>
+		bool CanResizeChild(DesignItem child);
+		
+		/// <summary>
+		/// Gets the placement for the drag frame adorner.
+		/// </summary>
+		/// <param name="child">The child being dragged</param>
+		/// <param name="horizontalChange">The horizontal change - positive=make larger, negative=make smaller</param>
+		/// <param name="verticalChange">The vertical change - positive=make larger, negative=make smaller</param>
+		/// <param name="horizontal">The orientation of the resize thumb used. This parameter may be used to determine on which side of the element the element grows/shrinks.</param>
+		/// <param name="vertical">The orientation of the resize thumb used. This parameter may be used to determine on which side of the element the element grows/shrinks.</param>
+		/// <returns>A placement describing the new location of the child being resized.</returns>
+		Placement GetPlacement(DesignItem child, double horizontalChange, double verticalChange, HorizontalAlignment horizontal, VerticalAlignment vertical);
+		
+		/// <summary>
+		/// Resizes the child.
+		/// </summary>
+		/// <param name="child">The child being dragged</param>
+		/// <param name="horizontalChange">The horizontal change - positive=make larger, negative=make smaller</param>
+		/// <param name="verticalChange">The vertical change - positive=make larger, negative=make smaller</param>
+		/// <param name="horizontal">The orientation of the resize thumb used. This parameter may be used to determine on which side of the element the element grows/shrinks.</param>
+		/// <param name="vertical">The orientation of the resize thumb used. This parameter may be used to determine on which side of the element the element grows/shrinks.</param>
+		/// <returns>A placement describing the new location of the child being resized.</returns>
+		void Resize(DesignItem child, double horizontalChange, double verticalChange, HorizontalAlignment horizontal, VerticalAlignment vertical);
+	}
+}
diff --git a/src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/WpfDesign.csproj b/src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/WpfDesign.csproj
index e5034278b9..3212622d4a 100644
--- a/src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/WpfDesign.csproj
+++ b/src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/WpfDesign.csproj
@@ -61,6 +61,7 @@
     <Compile Include="Adorners\AdornerProvider.cs" />
     <Compile Include="Adorners\AdornerProviderClasses.cs" />
     <Compile Include="Adorners\Placement.cs" />
+    <Compile Include="Behavior.cs" />
     <Compile Include="ChangeGroup.cs" />
     <Compile Include="DesignContext.cs" />
     <Compile Include="DesignItemProperty.cs" />