From 875c2b52c45d1d26ed088b9949fc44c41b193d5e Mon Sep 17 00:00:00 2001
From: John Lewin <lewin76@gmail.com>
Date: Wed, 16 Jan 2019 09:05:04 -0800
Subject: [PATCH] Fix null reference in edge case

---
 MatterControlLib/SlicerConfiguration/SliceSettingsWidget.cs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/MatterControlLib/SlicerConfiguration/SliceSettingsWidget.cs b/MatterControlLib/SlicerConfiguration/SliceSettingsWidget.cs
index 576f39b54..f370d3b76 100644
--- a/MatterControlLib/SlicerConfiguration/SliceSettingsWidget.cs
+++ b/MatterControlLib/SlicerConfiguration/SliceSettingsWidget.cs
@@ -919,7 +919,8 @@ namespace MatterHackers.MatterControl.SlicerConfiguration
 							userInitiated: false);
 					}
 
-					uifield.Row.UpdateValidationState(errors);
+					// Some fields are hosted outside of SettingsRows (e.g. Section Headers like Brim) and should skip validation updates
+					uifield.Row?.UpdateValidationState(errors);
 				}
 			}
 		}