fix possible NullReferenceException in SearchManager

src/AddIns/Misc/SearchAndReplace/Project/Engine/SearchManager.cs

@@ -461,9 +461,9 @@ namespace SearchAndReplace
 				return;
 			}
 			var editor = OpenTextArea(result.FileName, true);
+			if (editor != null) {
 				var start = editor.Document.PositionToOffset(result.StartLocation.Line, result.StartLocation.Column);
 				var end = editor.Document.PositionToOffset(result.EndLocation.Line, result.EndLocation.Column);
-			if (editor != null) {
 				editor.Caret.Offset = start;
 				editor.Select(start, end - start);
 			}