threading fix

src/MoonWorksMultiWindowGame.cs

@@ -48,11 +48,15 @@ namespace MoonWorksMultiWindow
 
         protected override void Draw(System.TimeSpan dt, double alpha)
         {
-			Task mainDraw = Task.Run(MainDraw);
-			Task extraDraw = Task.Run(ExtraWindowDraw);
+			var mainDraw = Task.Run(MainDraw);
+			var extraDraw = Task.Run(ExtraWindowDraw);
+
+			mainDraw.Wait();
+			extraDraw.Wait();
+			GraphicsDevice.Submit(mainDraw.Result, extraDraw.Result);
         }
 
-		private void MainDraw()
+		private CommandBuffer MainDraw()
 		{
             var commandBuffer = GraphicsDevice.AcquireCommandBuffer();
 
@@ -77,10 +81,10 @@ namespace MoonWorksMultiWindow
 				Window
             );
 
-            GraphicsDevice.Submit(commandBuffer);
+			return commandBuffer;
 		}
 
-		private void ExtraWindowDraw()
+		private CommandBuffer ExtraWindowDraw()
 		{
 			var commandBuffer = GraphicsDevice.AcquireCommandBuffer();
 
@@ -105,7 +109,7 @@ namespace MoonWorksMultiWindow
 				ExtraWindow
 			);
 
-			GraphicsDevice.Submit(commandBuffer);
+			return commandBuffer;
 		}
     }
 }