A better fix

OpenRA.Game/Selection.cs

@@ -52,7 +52,11 @@ namespace OpenRA
 
 		public IEnumerable<Actor> Actors { get { return actors; } }
 		public void Clear() { actors = new List<Actor>(); }
-
+		public void Remove(Actor a)
+		{
+			actors.Remove(a);
+		}
+		
 		public void Tick(World world)
 		{
 			actors.RemoveAll(a => !a.IsInWorld);

OpenRA.Game/World.cs

@@ -136,6 +136,9 @@ namespace OpenRA
 		public void Remove(Actor a)
 		{
 			a.IsInWorld = false;
+			if (Selection.Contains(a))
+				Selection.Remove(a);
+			
 			actors.Remove(a);
 			ActorRemoved(a);
 		}

OpenRA.Mods.RA/World/ChooseBuildTabOnSelect.cs

@@ -31,8 +31,8 @@ namespace OpenRA.Mods.RA.Widgets
 		public void SelectionChanged()
 		{
 			// Queue-per-structure
-			var perqueue = world.Selection.Actors.FirstOrDefault(
-				a => a.IsInWorld && a.World.LocalPlayer == a.Owner && a.HasTrait<ProductionQueue>());
+			var perqueue = world.Selection.Actors.FirstOrDefault(a => 
+				a.World.LocalPlayer == a.Owner && a.HasTrait<ProductionQueue>());
 			
 			if (perqueue != null)
 			{
@@ -42,8 +42,7 @@ namespace OpenRA.Mods.RA.Widgets
 			}
 			
 			// Queue-per-player
-			var types = world.Selection.Actors.Where(a => a.IsInWorld)
-											  .SelectMany(a => a.TraitsImplementing<Production>())
+			var types = world.Selection.Actors.SelectMany(a => a.TraitsImplementing<Production>())
 											  .SelectMany(t => t.Info.Produces)
 											  .Distinct();