rel #23802: show message if no category selected

library/ZendAfi/View/Helper/SitoTree.php

@@ -30,6 +30,9 @@ class ZendAfi_View_Helper_SitoTree extends ZendAfi_View_Helper_BaseHelper {
 
 
 	protected function renderHierarchicalCategories($category, $max_display) {
+		if (!$category)
+			return $this->_('Aucune catégorie sélectionnée.');
+
 		$html = '';
 		$children = $category->getChildren();
 		foreach (array_slice($children, 0, $max_display) as $child_category)