diff --git a/htdocs/core/class/commonobject.class.php b/htdocs/core/class/commonobject.class.php
index 5d6771d88df..2bd32df1f05 100644
--- a/htdocs/core/class/commonobject.class.php
+++ b/htdocs/core/class/commonobject.class.php
@@ -5009,7 +5009,7 @@ abstract class CommonObject
 			{
 				$value_arr = GETPOST($postfieldkey, 'array'); // check if an array
 				if (!empty($value_arr)) {
-					$value_key = implode($value_arr, ',');
+					$value_key = implode(',', $value_arr);
 				} else {
 					$value_key = '';
 				}
@@ -5801,7 +5801,7 @@ abstract class CommonObject
 	 *
 	 * @param  array   		$val	       Array of properties for field to show (used only if ->fields not defined)
 	 * @param  string  		$key           Key of attribute
-	 * @param  string  		$value         Preselected value to show (for date type it must be in timestamp format, for amount or price it must be a php numeric value)
+	 * @param  string|array	$value         Preselected value to show (for date type it must be in timestamp format, for amount or price it must be a php numeric value, for array type must be array)
 	 * @param  string  		$moreparam     To add more parameters on html input tag
 	 * @param  string  		$keysuffix     Prefix string to add into name and id of field (can be used to avoid duplicate names)
 	 * @param  string  		$keyprefix     Suffix string to add into name and id of field (can be used to avoid duplicate names)