diff --git a/OpenRA.Game/Orders/UnitOrderGenerator.cs b/OpenRA.Game/Orders/UnitOrderGenerator.cs
index d088a8a75b..0e72be2991 100644
--- a/OpenRA.Game/Orders/UnitOrderGenerator.cs
+++ b/OpenRA.Game/Orders/UnitOrderGenerator.cs
@@ -45,17 +45,17 @@ namespace OpenRA.Orders
 			foreach (var a in world.Selection.Actors)
 				if (!a.Destroyed)
 					foreach (var t in a.TraitsImplementing<IPreRenderSelection>())
-						t.RenderBeforeWorld(a);
-
+						t.RenderBeforeWorld(a);
+
 			Game.Renderer.Flush();
 		}
 
 		public void RenderAfterWorld( World world )
 		{
-			foreach (var a in world.Selection.Actors)
+			foreach (var a in world.Selection.Actors)
 				if (!a.Destroyed)
 					foreach (var t in a.TraitsImplementing<IPostRenderSelection>())
-						t.RenderAfterWorld(a);
+						t.RenderAfterWorld(a);
 
 			Game.Renderer.Flush();
 		}
diff --git a/OpenRA.Game/Sync.cs b/OpenRA.Game/Sync.cs
index 6ed32a3498..efe072cefd 100755
--- a/OpenRA.Game/Sync.cs
+++ b/OpenRA.Game/Sync.cs
@@ -132,19 +132,31 @@ namespace OpenRA
 
 		public static void CheckSyncUnchanged( World world, Action fn )
 		{
-			int sync = world.SyncHash();
-			fn();
-			if( sync != world.SyncHash() )
-				throw new InvalidOperationException( "Desync in DispatchMouseInput" );
+			CheckSyncUnchanged( world, () => { fn(); return true; } );
 		}
 
+		static bool inUnsyncedCode = false;
+
 		public static T CheckSyncUnchanged<T>( World world, Func<T> fn )
 		{
 			int sync = world.SyncHash();
-			var ret = fn();
-			if( sync != world.SyncHash() )
-				throw new InvalidOperationException( "Desync in DispatchMouseInput" );
-			return ret;
+			inUnsyncedCode = true;
+			try
+			{
+				return fn();
+			}
+			finally
+			{
+				inUnsyncedCode = false;
+				if( sync != world.SyncHash() )
+					throw new InvalidOperationException( "Desync in DispatchMouseInput" );
+			}
+		}
+
+		public static void AssertUnsynced( string message )
+		{
+			if( !inUnsyncedCode )
+				throw new InvalidOperationException( message );
 		}
 	}
 }
diff --git a/OpenRA.Game/World.cs b/OpenRA.Game/World.cs
index 90496cffcc..7a57be92df 100644
--- a/OpenRA.Game/World.cs
+++ b/OpenRA.Game/World.cs
@@ -54,8 +54,18 @@ namespace OpenRA
 		public readonly TileSet TileSet;
 
 		public readonly WorldRenderer WorldRenderer;
-		
-		public IOrderGenerator OrderGenerator = new UnitOrderGenerator();
+
+		IOrderGenerator orderGenerator_;
+		public IOrderGenerator OrderGenerator
+		{
+			get { return orderGenerator_; }
+			set
+			{
+				Sync.AssertUnsynced( "The current order generator may not be changed from synced code" );
+				orderGenerator_ = value;
+			}
+		}
+
 		public Selection Selection = new Selection();
 
 		public void CancelInputMode() { OrderGenerator = new UnitOrderGenerator(); }
@@ -76,6 +86,7 @@ namespace OpenRA
 		
 		public World(Manifest manifest, Map map)
 		{
+			orderGenerator_ = new UnitOrderGenerator();
 			Map = map;
 			
 			TileSet = Rules.TileSets[Map.Tileset];