diff --git a/includes/workbench_access_handler_filter_access.inc b/includes/workbench_access_handler_filter_access.inc
index 42781d2..2e5a51a 100644
--- a/includes/workbench_access_handler_filter_access.inc
+++ b/includes/workbench_access_handler_filter_access.inc
@@ -115,13 +115,13 @@ class workbench_access_handler_filter_access extends views_handler_filter_many_t
     }
 
     // If there is no selection, use the user's own access tree.
-    if (empty($this->value[0]) || $this->value[0] == -5) {
+    if (!is_array($this->value) && $this->value == -5) {
       workbench_access_build_tree($tree, array_keys($account->workbench_access));
       $group = $this->query->set_where_group('OR');
       $node_type_filter = TRUE;
     }
     else {
-      workbench_access_build_tree($tree, array_keys($this->value[0]));
+      workbench_access_build_tree($tree, (array) $this->value);
       $group = $this->query->set_where_group('AND');
       $node_type_filter = FALSE;
     }