diff --git a/htdocs/product/list.php b/htdocs/product/list.php
index a3ec599dea8..778565dd2cb 100644
--- a/htdocs/product/list.php
+++ b/htdocs/product/list.php
@@ -65,7 +65,12 @@ $search_barcode = GETPOST("search_barcode", 'alpha');
 $search_label = GETPOST("search_label", 'alpha');
 $search_type = GETPOST("search_type", 'int');
 $search_vatrate = GETPOST("search_vatrate", 'alpha');
-$searchCategoryProductOperator = (GETPOST('search_category_product_operator', 'int') ? GETPOST('search_category_product_operator', 'int') : 0);
+$searchCategoryProductOperator = 0;
+if (GETPOSTISSET('formfilteraction')) {
+	$searchCategoryProductOperator = GETPOST('search_category_product_operator', 'int');
+} elseif (!empty($conf->global->MAIN_SEARCH_CAT_OR_BY_DEFAULT)) {
+	$searchCategoryProductOperator = $conf->global->MAIN_SEARCH_CAT_OR_BY_DEFAULT;
+}
 $searchCategoryProductList = GETPOST('search_category_product_list', 'array');
 $search_tosell = GETPOST("search_tosell", 'int');
 $search_tobuy = GETPOST("search_tobuy", 'int');