[HistoryLayer] On viewmodel changes we ensure our viewmodel is not null and set default color

1 files changed, 5 insertions, 1 deletions

diff --git a/Xamarin.PropertyEditing.Mac/Controls/Custom/HistoryLayer.cs b/Xamarin.PropertyEditing.Mac/Controls/Custom/HistoryLayer.cs
index 9f90d61..48baebb 100644
--- a/Xamarin.PropertyEditing.Mac/Controls/Custom/HistoryLayer.cs
+++ b/Xamarin.PropertyEditing.Mac/Controls/Custom/HistoryLayer.cs
@@ -78,7 +78,11 @@ namespace Xamarin.PropertyEditing.Mac
 		{
 			LayoutIfNeeded ();
 			current.BackgroundColor = interaction.Color.ToCGColor ();
-			previous.BackgroundColor = interaction.ViewModel.InitialColor.ToCGColor ();
+			//there are some scenarios where viewmodel could be null
+			var initialColor = interaction.ViewModel?.InitialColor;
+			if (initialColor != null) {
+				previous.BackgroundColor = initialColor.ToCGColor ();
+			}
 			last.BackgroundColor = interaction.LastColor.ToCGColor ();
 		}