// fix category_tree if no tree

admin-dev/themes/template/products/list_header.tpl

@@ -11,6 +11,7 @@
 		});
 	});
 </script>
+{if isset($category_tree)}
 	{l s='Go to category:'}
 	<select id="go_to_categ" name="go_to_categ">
 	{foreach from=$category_tree item=categ}
@@ -19,4 +20,5 @@
 		</option>
 	{/foreach}
 	</select>
+{/if}
 {/block}