missing pieces of selling

OpenRa.Game/Controller.cs

@@ -183,6 +183,7 @@ namespace OpenRa.Game
 			case "Harvest": return Cursor.Attack; // TODO: special harvest cursor?
 			case "PlaceBuilding": return Cursor.Default;
 			case "Sell": return Cursor.Sell;
+			case "NoSell": return Cursor.SellBlocked;
 			default:
 				return null;
 			}

OpenRa.Game/Cursor.cs

@@ -27,5 +27,6 @@ namespace OpenRa.Game
 		public static Cursor Capture { get { return new Cursor("capture"); } }
 		public static Cursor Heal { get { return new Cursor("heal"); } }
 		public static Cursor Sell { get { return new Cursor("sell"); } }
+		public static Cursor SellBlocked { get { return new Cursor("sell-blocked"); } }
 	}
 }

OpenRa.Game/Orders/SellOrderGenerator.cs

@@ -11,18 +11,25 @@ namespace OpenRa.Game.Orders
 	{
 		public IEnumerable<Order> Order(int2 xy, MouseInput mi)
 		{
+			if (!mi.IsFake && mi.Button == MouseButton.Right)
+			{
+				Game.controller.CancelInputMode();
+				yield break;
+			}
+
 			var loc = mi.Location + Game.viewport.Location;
 			var underCursor = Game.FindUnits(loc, loc)
 				.Where(a => a.Owner == Game.LocalPlayer
 					&& a.traits.Contains<Building>()
 					&& a.Info.Selectable).FirstOrDefault();
 
-			if (underCursor == null)
-				yield break;
+			var building = underCursor != null ? underCursor.Info as BuildingInfo : null;
 
-			var building = underCursor.traits.Get<Building>();
-			if (building.unitInfo.Unsellable)
+			if (building == null || building.Unsellable)
+			{
+				yield return new Order("NoSell", Game.LocalPlayer.PlayerActor, null, int2.Zero, null);
 				yield break;
+			}
 
 			yield return new Order("Sell", underCursor, null, int2.Zero, null);
 		}