From 8ca264b0b0f7965c5faf411db2f82c941cd03eff Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Fri, 1 May 2009 05:07:41 +0000
Subject: [PATCH] MINOR Merged from branches/2.3

git-svn-id: svn://svn.silverstripe.com/silverstripe/open/modules/sapphire/trunk@75875 467b73ca-7a2a-4603-9d3b-597d59a354a9
---
 forms/TreeDropdownField.php | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/forms/TreeDropdownField.php b/forms/TreeDropdownField.php
index e7968ee13..3a7501dea 100755
--- a/forms/TreeDropdownField.php
+++ b/forms/TreeDropdownField.php
@@ -99,6 +99,9 @@ HTML;
 		echo substr(trim($tree), 4,-5);
 	}
 	
+	/**
+	 * @return DataObject
+	 */
 	public function getByKey($key) {
 		if($this->keyField == 'ID') {
 			return DataObject::get_by_id($this->sourceObject, $key);
@@ -124,9 +127,13 @@ HTML;
 
 	function performReadonlyTransformation() {
 		$fieldName = $this->labelField;
-		$value = ($this->getByKey($this->value)) ? $this->getByKey($this->value)->$fieldName : '';
+		if($this->value) {
+			$obj = ($this->getByKey($this->value)) ? $this->getByKey($this->value)->$fieldName : '';
+		} else {
+			$obj = null;
+		}
 		$source = array(
-			$this->value => $value
+			$this->value => $obj
 		);
 		$field = new LookupField($this->name, $this->title, $source);
 		$field->setValue($this->value);