Fix: compatibility with external module and hook

htdocs/core/class/commonobject.class.php

@@ -1438,9 +1438,9 @@ class CommonObject
 		{
 			$var=!$var;
 
-			if ($line->product_type == 9 && ! empty($line->special_code))
+			if (($line->product_type == 9 && ! empty($line->special_code)) || ! empty($line->fk_parent_line))
 			{
-				$this->hooks[$line->special_code]->printObjectLine($this,$line,$num,$i);
+				if (empty($line->fk_parent_line)) $this->hooks[$line->special_code]->printObjectLine($this,$line,$num,$i);
 			}
 			else
 			{