Index: class/System/Test/System.ComponentModel/ContainerTest.cs
===================================================================
--- class/System/Test/System.ComponentModel/ContainerTest.cs	(revision 61911)
+++ class/System/Test/System.ComponentModel/ContainerTest.cs	(working copy)
@@ -3,8 +3,10 @@
 //
 // Authors:
 // 	Gonzalo Paniagua Javier (gonzalo@ximian.com)
-//
+//  Ivan N. Zlatev (contact i-nZ.net)
+
 // Copyright (c) 2006 Novell, Inc. (http://www.novell.com)
+// Copyright (c) 2006 Ivan N. Zlatev
 //
 
 using NUnit.Framework;
@@ -27,6 +29,26 @@
 		protected override object GetService( Type serviceType ) {
 			return _services.GetService( serviceType );
 		}
+
+#if NET_2_0
+		public void Remove_WithoutUnsiting (IComponent component)
+		{
+			base.RemoveWithoutUnsiting (component);
+		}
+#endif
+		
+		public bool Contains (IComponent component)
+		{
+			bool found = false;
+			
+			foreach (IComponent c in Components) {
+				if (component.Equals (c)) {
+					found = true;
+					break;
+				}
+			}
+			return found;
+		}
 	}
 	
 	class TestComponent : Component {
@@ -45,12 +67,45 @@
 	}
 
 	[TestFixture]
-	public class ContainerTest {
+	public class ContainerTest
+	{
+		
+		private TestContainer _container;
+		
+		[SetUp]
+		public void Init ()
+		{
+			_container = new TestContainer ();
+		}
+
+		
 		[Test]
+		public void AddRemove ()
+		{
+			bool found = false;		   
+			TestComponent component = new TestComponent ();
+			
+			_container.Add (component);
+			Assert.IsNotNull (component.Site, "#1");			
+			Assert.IsTrue (_container.Contains (component), "#2");
+			
+			_container.Remove (component);
+			Assert.IsNull (component.Site, "#3");
+			Assert.IsFalse (_container.Contains (component), "#4");
+			
+#if NET_2_0
+			_container.Add (component);
+			_container.Remove_WithoutUnsiting (component);
+			Assert.IsNotNull (component.Site, "#5");
+			Assert.IsFalse (_container.Contains (component), "#6");
+#endif
+		}
+
+		
+		[Test]
 		public void GetService1 ()
 		{
-			TestContainer container = new TestContainer ();
-			container.Add (new TestComponent ());
+			_container.Add (new TestComponent ());
 		}
 	}
 }
Index: class/System/System.ComponentModel/Container.cs
===================================================================
--- class/System/System.ComponentModel/Container.cs	(revision 61911)
+++ class/System/System.ComponentModel/Container.cs	(working copy)
@@ -4,9 +4,11 @@
 // Author:
 //  Miguel de Icaza (miguel@ximian.com)
 //  Andreas Nahr (ClassDevelopment@A-SoftTech.com)
+//  Ivan N. Zlatev (contact i-nZ.net)
 //
 // (C) Ximian, Inc.  http://www.ximian.com
 // (C) 2003 Andreas Nahr
+// (C) 2006 Ivan N. Zlatev
 //
 
 //
@@ -58,6 +60,7 @@
 		// </remarks>
 		
 		class DefaultSite : ISite {
+
 			private IComponent component;
 			private Container container;
 			private string     name;
@@ -81,11 +84,8 @@
 				}
 			}
 
-			[MonoTODO]
 			public bool DesignMode {
 				get {
-					// FIXME: should we provide a way to set
-					// this value?
 					return false;
 				}
 			}
@@ -130,19 +130,20 @@
 
 		public virtual void Add (IComponent component, string name)
 		{
-			component.Site = CreateSite (component, name);
-			c.Add (component);
+			if (component != null) {
+				if (component.Site == null || component.Site.Container != this) {					
+					if (component.Site != null) {
+						component.Site.Container.Remove (component);
+					}
+					
+					component.Site = this.CreateSite (component, name);
+					c.Add (component);
+				}
+			}
 		}
 
 		protected virtual ISite CreateSite (IComponent component, string name)
 		{
-			if (name != null) {
-				foreach (IComponent Comp in c) {
-					if (Comp.Site != null && Comp.Site.Name == name)
-						throw new ArgumentException ("duplicate component name", "name");
-				}
-			}
-
 			return new DefaultSite (name, component, this);
 		}
 
@@ -183,8 +184,28 @@
 
 		public virtual void Remove (IComponent component)
 		{
-			c.Remove (component);
+			Remove (component, true);		
 		}
+
+		private void Remove (IComponent component, bool unsite)
+		{
+			if (component.Site != null && component.Site.Container == this) {
+				if (unsite) {
+					component.Site = null;
+				}
+				c.Remove (component);
+			}					
+		}
+
+#if NET_2_0
+		protected void RemoveWithoutUnsiting (IComponent component)
+		{
+			if (component.Site != null && component.Site.Container == this) {
+				Remove (component, false);
+			}
+		}
+#endif
+		
 	}
 	
 }