diff --git a/PartPreviewWindow/RunningTasksWidget.cs b/PartPreviewWindow/RunningTasksWidget.cs
index 2ecf454c7..85660e52a 100644
--- a/PartPreviewWindow/RunningTasksWidget.cs
+++ b/PartPreviewWindow/RunningTasksWidget.cs
@@ -90,7 +90,7 @@ namespace MatterHackers.MatterControl.PartPreviewWindow
 				}
 			}
 
-			var progressBackgroundColor = borderColor.AdjustAlpha(35);
+			var progressBackgroundColor = new Color(borderColor, 35);
 
 			// Add new items
 			foreach (var taskItem in tasks.RunningTasks.Where(t => !displayedTasks.Contains(t)))