Press "Alt" key to Enter a Container, do not Enter automatically.

Show a Info Text in the Container so that the User knows this!
=> same Behavior like in VS, because when you Enter automaticaly you can not move Contrls on Top of a Container with the Mouse

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Controls/InfoTextEnterArea.cs

@@ -0,0 +1,101 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
+// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
+
+using System;
+using System.Diagnostics;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Media;
+using System.Windows.Threading;
+using System.Windows.Media.Animation;
+using ICSharpCode.WpfDesign.Adorners;
+using ICSharpCode.WpfDesign.Designer.Services;
+
+namespace ICSharpCode.WpfDesign.Designer.Controls
+{
+	/// <summary>
+	/// Gray out everything except a specific area.
+	/// </summary>
+	sealed class InfoTextEnterArea : FrameworkElement
+	{
+		Geometry designSurfaceRectangle;
+		Geometry activeAreaGeometry;
+		Geometry combinedGeometry;
+		AdornerPanel adornerPanel;
+		IDesignPanel designPanel;
+		const double MaxOpacity = 0.3;
+		
+		public InfoTextEnterArea()
+		{
+			this.IsHitTestVisible = false;
+		}		
+			
+		public Geometry ActiveAreaGeometry {
+			get { return activeAreaGeometry; }
+			set {
+				activeAreaGeometry = value;
+				combinedGeometry = activeAreaGeometry;
+			}
+		}		
+		
+		Rect currentAnimateActiveAreaRectToTarget;
+		
+		internal void AnimateActiveAreaRectTo(Rect newRect)
+		{
+			if (newRect.Equals(currentAnimateActiveAreaRectToTarget))
+				return;
+			activeAreaGeometry.BeginAnimation(
+				RectangleGeometry.RectProperty,
+				new RectAnimation(newRect, new Duration(new TimeSpan(0,0,0,0,100))),
+				HandoffBehavior.SnapshotAndReplace);
+			currentAnimateActiveAreaRectToTarget = newRect;
+		}
+		
+		internal static void Start(ref InfoTextEnterArea grayOut, ServiceContainer services, UIElement activeContainer, string text)
+		{
+			Debug.Assert(activeContainer != null);
+			Start(ref grayOut, services, activeContainer, new Rect(activeContainer.RenderSize), text);
+		}
+		
+		internal static void Start(ref InfoTextEnterArea grayOut, ServiceContainer services, UIElement activeContainer, Rect activeRectInActiveContainer, string text)
+		{
+			Debug.Assert(services != null);
+			Debug.Assert(activeContainer != null);
+			DesignPanel designPanel = services.GetService<IDesignPanel>() as DesignPanel;
+			OptionService optionService = services.GetService<OptionService>();
+			if (designPanel != null && grayOut == null && optionService != null && optionService.GrayOutDesignSurfaceExceptParentContainerWhenDragging) {
+				grayOut = new InfoTextEnterArea();
+				grayOut.designSurfaceRectangle = new RectangleGeometry(
+					new Rect(0, 0, ((Border)designPanel.Child).Child.RenderSize.Width, ((Border)designPanel.Child).Child.RenderSize.Height));
+				grayOut.designPanel = designPanel;
+				grayOut.adornerPanel = new AdornerPanel();
+				grayOut.adornerPanel.Order = AdornerOrder.Background;
+				grayOut.adornerPanel.SetAdornedElement(designPanel.Context.RootItem.View, null);
+				grayOut.ActiveAreaGeometry = new RectangleGeometry(activeRectInActiveContainer, 0, 0, (Transform)activeContainer.TransformToVisual(grayOut.adornerPanel.AdornedElement));
+				var tb = new TextBlock(){Text = text};
+				tb.FontSize = 10;
+				tb.ClipToBounds = true;
+				tb.Width = ((FrameworkElement) activeContainer).ActualWidth;
+				tb.Height = ((FrameworkElement) activeContainer).ActualHeight;
+				tb.VerticalAlignment = VerticalAlignment.Top;
+				tb.HorizontalAlignment = HorizontalAlignment.Left;
+				tb.RenderTransform = (Transform)activeContainer.TransformToVisual(grayOut.adornerPanel.AdornedElement);
+				grayOut.adornerPanel.Children.Add(tb);
+								
+				designPanel.Adorners.Add(grayOut.adornerPanel);
+			}
+		}
+		
+		static readonly TimeSpan animationTime = new TimeSpan(2000000);
+		
+		internal static void Stop(ref InfoTextEnterArea grayOut)
+		{
+			if (grayOut != null) {
+				IDesignPanel designPanel = grayOut.designPanel;
+				AdornerPanel adornerPanelToRemove = grayOut.adornerPanel;
+				designPanel.Adorners.Remove(adornerPanelToRemove);								
+				grayOut = null;
+			}
+		}
+	}
+}

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Extensions/DefaultPlacementBehavior.cs

@@ -5,6 +5,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
+using System.Windows.Input;
 using ICSharpCode.WpfDesign.Extensions;
 using System.Windows.Controls;
 using System.Windows;
@@ -32,7 +33,7 @@ namespace ICSharpCode.WpfDesign.Designer.Extensions
 			_contentControlsNotAllowedToAdd.Add(typeof (HeaderedContentControl));
 			_contentControlsNotAllowedToAdd.Add(typeof (Label));
 			_contentControlsNotAllowedToAdd.Add(typeof (ListBoxItem));
-			_contentControlsNotAllowedToAdd.Add(typeof (ButtonBase));
+			//_contentControlsNotAllowedToAdd.Add(typeof (ButtonBase));
 			_contentControlsNotAllowedToAdd.Add(typeof (StatusBarItem));
 			_contentControlsNotAllowedToAdd.Add(typeof (ToolTip));
 		}
@@ -63,6 +64,7 @@ namespace ICSharpCode.WpfDesign.Designer.Extensions
 
 		public virtual void EndPlacement(PlacementOperation operation)
 		{
+			InfoTextEnterArea.Stop(ref infoTextEnterArea);			
 		}
 
 		public virtual Rect GetPosition(PlacementOperation operation, DesignItem item)
@@ -98,8 +100,27 @@ namespace ICSharpCode.WpfDesign.Designer.Extensions
 			}
 		}
 
-		public virtual bool CanEnterContainer(PlacementOperation operation)
+		private static InfoTextEnterArea infoTextEnterArea;
+		
+		public virtual bool CanEnterContainer(PlacementOperation operation, bool shouldAlwaysEnter)
+		{
+			var canEnter = internalCanEnterContainer(operation);
+			
+			if (canEnter && !shouldAlwaysEnter && !Keyboard.IsKeyDown(Key.LeftAlt) && !Keyboard.IsKeyDown(Key.RightAlt))
+			{
+				var b = new Rect(0, 0, ((FrameworkElement)this.ExtendedItem.View).ActualWidth, ((FrameworkElement)this.ExtendedItem.View).ActualHeight);
+				InfoTextEnterArea.Start(ref infoTextEnterArea, this.Services, this.ExtendedItem.View, b, "Press \"Alt\" to Enter Container");						
+				
+				return false;
+			}
+			
+			return canEnter;
+		}
+		
+		private bool internalCanEnterContainer(PlacementOperation operation)
 		{
+			InfoTextEnterArea.Stop(ref infoTextEnterArea);												
+			
 			if (ExtendedItem.Component is Expander)
 			{
 				if (!((Expander) ExtendedItem.Component).IsExpanded)

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/OutlineView/OutlineNode.cs

@@ -178,7 +178,7 @@ namespace ICSharpCode.WpfDesign.Designer.OutlineView
 				return false;
 			var operation = PlacementOperation.Start(nodes.Select(node => node.DesignItem).ToArray(), DummyPlacementType);
 			if (operation != null) {
-				bool canEnter = placementBehavior.CanEnterContainer(operation);
+				bool canEnter = placementBehavior.CanEnterContainer(operation, true);
 				operation.Abort();
 				return canEnter;
 			}

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/RootItemBehavior.cs

@@ -73,7 +73,7 @@ namespace ICSharpCode.WpfDesign.Designer
 			throw new NotImplementedException();
 		}
 		
-		public bool CanEnterContainer(PlacementOperation operation)
+		public bool CanEnterContainer(PlacementOperation operation, bool shouldAlwaysEnter)
 		{
 			return false;
 		}

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Services/MoveLogic.cs

@@ -128,7 +128,7 @@ namespace ICSharpCode.WpfDesign.Designer.Services
 			}
 			
 			IPlacementBehavior b = result.ModelHit.GetBehavior<IPlacementBehavior>();
-			if (b != null && b.CanEnterContainer(operation)) {
+			if (b != null && b.CanEnterContainer(operation, false)) {
 				operation.ChangeContainer(result.ModelHit);
 				return true;
 			}

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/WpfDesign.Designer.csproj

@@ -87,6 +87,7 @@
       <DependentUpon>EnumBar.xaml</DependentUpon>
     </Compile>
     <Compile Include="Controls\EnumButton.cs" />
+    <Compile Include="Controls\InfoTextEnterArea.cs" />
     <Compile Include="Controls\GrayOutDesignerExceptActiveArea.cs">
       <SubType>Code</SubType>
     </Compile>

src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/PlacementBehavior.cs

@@ -57,7 +57,7 @@ namespace ICSharpCode.WpfDesign
 		/// <summary>
 		/// Gets if entering this container is allowed for the specified operation.
 		/// </summary>
-		bool CanEnterContainer(PlacementOperation operation);
+		bool CanEnterContainer(PlacementOperation operation, bool shouldAlwaysEnter);
 		
 		/// <summary>
 		/// Let the placed children enter this container.

src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/PlacementOperation.cs

@@ -246,7 +246,7 @@ namespace ICSharpCode.WpfDesign
 				}
 				op.currentContainer = container;
 				op.currentContainerBehavior = container.GetBehavior<IPlacementBehavior>();
-				if (op.currentContainerBehavior == null || !op.currentContainerBehavior.CanEnterContainer(op)) {
+				if (op.currentContainerBehavior == null || !op.currentContainerBehavior.CanEnterContainer(op, true)) {
 					op.changeGroup.Abort();
 					return null;
 				}