From 843b9355a19b7de187530a32e00f0e1fba30a07a Mon Sep 17 00:00:00 2001
From: GreatFireWall <GreatFireWall@users.noreply.github.com>
Date: Sat, 22 Feb 2020 17:39:18 +0800
Subject: [PATCH] Fix ArgumentNullException issue.

---
 ICSharpCode.AvalonEdit/Search/SearchPanel.cs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/ICSharpCode.AvalonEdit/Search/SearchPanel.cs b/ICSharpCode.AvalonEdit/Search/SearchPanel.cs
index 9374428..d8e37c0 100644
--- a/ICSharpCode.AvalonEdit/Search/SearchPanel.cs
+++ b/ICSharpCode.AvalonEdit/Search/SearchPanel.cs
@@ -272,10 +272,15 @@ namespace ICSharpCode.AvalonEdit.Search
 		{
 			if (searchTextBox == null)
 				return;
+
 			var be = searchTextBox.GetBindingExpression(TextBox.TextProperty);
+
 			try {
-				Validation.ClearInvalid(be);
+				if (be != null)
+					Validation.ClearInvalid(be);
+
 				UpdateSearch();
+
 			} catch (SearchPatternException ex) {
 				var ve = new ValidationError(be.ParentBinding.ValidationRules[0], be, ex.Message, ex);
 				Validation.MarkInvalid(be, ve);