diff --git a/ReoGrid/Views/NormalViewportController.cs b/ReoGrid/Views/NormalViewportController.cs
index cba25de3..86a57f52 100644
--- a/ReoGrid/Views/NormalViewportController.cs
+++ b/ReoGrid/Views/NormalViewportController.cs
@@ -914,7 +914,9 @@ public virtual void ScrollViews(ScrollDirection dir, RGFloat x, RGFloat y)
 
 			foreach (var v in this.view.Children)
 			{
-				if (v is IViewport vp)
+				var vp = (v as IViewport);
+
+				if (vp != null)
 				{
 					if (vp.ScrollableDirections == dir)
 					{