Index: workspaces/Classes/ExtDirect/Server.php
===================================================================
--- workspaces/Classes/ExtDirect/Server.php	(Revision 3856)
+++ workspaces/Classes/ExtDirect/Server.php	(Arbeitskopie)
@@ -80,10 +80,6 @@
 		global $TCA,$BE_USER;
 		$diffReturnArray = array();
 		$liveReturnArray = array();
-		/**
-		 * @todo  make sure this would work in local extension installation too
-		 */
-		$backPath = isset($GLOBALS['BACK_PATH']) ? $GLOBALS['BACK_PATH'] : '../../../' . TYPO3_mainDir;
 
 		$t3lib_diff = t3lib_div::makeInstance('t3lib_diff');
 		$stagesService = t3lib_div::makeInstance('Tx_Workspaces_Service_Stages');
@@ -116,8 +112,8 @@
 					$fieldTitle = $GLOBALS['LANG']->sL(t3lib_BEfunc::getItemLabel($parameter->table, $fieldName));
 
 					if ($TCA[$parameter->table]['columns'][$fieldName]['config']['type'] == 'group' && $TCA[$parameter->table]['columns'][$fieldName]['config']['internal_type'] == 'file') {
-						$versionThumb = t3lib_BEfunc::thumbCode($versionRecord, $parameter->table, $fieldName, $backPath);
-						$liveThumb = t3lib_BEfunc::thumbCode($liveRecord, $parameter->table, $fieldName, $backPath);
+						$versionThumb = t3lib_BEfunc::thumbCode($versionRecord, $parameter->table, $fieldName, '');
+						$liveThumb = t3lib_BEfunc::thumbCode($liveRecord, $parameter->table, $fieldName, '');
 
 						$diffReturnArray[] = array(
 							'label' => $fieldTitle,