diff --git a/htdocs/accountancy/admin/categories.php b/htdocs/accountancy/admin/categories.php
index 2a15921243f..7b660419daf 100644
--- a/htdocs/accountancy/admin/categories.php
+++ b/htdocs/accountancy/admin/categories.php
@@ -182,7 +182,7 @@ if ((empty($action) || $action == 'display' || $action == 'delete') && $cat_id >
 		}
 
 		if (is_array($accountingcategory->lines_display) && count($accountingcategory->lines_display) > 0) {
-			$accountingcategory->lines_display = dol_sort_array($accountingcategory->lines_display, $sortfield, $sortorder, 1, 0, 1);
+			$accountingcategory->lines_display = dol_sort_array($accountingcategory->lines_display, $sortfield, $sortorder, -1, 0, 1);
 
 			foreach ($accountingcategory->lines_display as $cpt) {
 				print '<tr class="oddeven">';
diff --git a/htdocs/core/lib/functions.lib.php b/htdocs/core/lib/functions.lib.php
index cc32224ff2b..85cb8a9cdfe 100644
--- a/htdocs/core/lib/functions.lib.php
+++ b/htdocs/core/lib/functions.lib.php
@@ -8671,7 +8671,8 @@ function dol_htmloutput_errors($mesgstring = '', $mesgarray = array(), $keepembe
  *  @param      array		$array      		Array to sort (array of array('key1'=>val1,'key2'=>val2,'key3'...) or array of objects)
  *  @param      string		$index				Key in array to use for sorting criteria
  *  @param      int			$order				Sort order ('asc' or 'desc')
- *  @param      int			$natsort			1=use "natural" sort (natsort) for a search criteria thats is strings or unknown, 0=use "standard" sort (asort) for numbers
+ *  @param      int			$natsort			If values are strings (I said value not type): 0=Use alphabetical order, 1=use "natural" sort (natsort)
+ *   											If values are numeric (I said value not type): 0=Use numeric order (even if type is string) so use a "natural" sort, 1=use "natural" sort too (same than 0), -1=Force alphabetical order
  *  @param      int			$case_sensitive		1=sort is case sensitive, 0=not case sensitive
  *  @param		int			$keepindex			If 0 and index key of array to sort is a numeric, than index will be rewrote. If 1 or index key is not numeric, key for index is kept after sorting.
  *  @return     array							Sorted array
@@ -8691,9 +8692,12 @@ function dol_sort_array(&$array, $index, $order = 'asc', $natsort = 0, $case_sen
 				} else {
 					$temp[$key] = empty($array[$key][$index]) ? 0 : $array[$key][$index];
 				}
+				if ($natsort == -1) {
+					$temp[$key] = '___'.$temp[$key];        // We add a string at begin of value to force an alpha order when using asort.
+				}
 			}
 
-			if (!$natsort) {
+			if (empty($natsort) || $natsort == -1) {
 				if ($order == 'asc') {
 					asort($temp);
 				} else {