php - Moodle 2.8.5+:How to set new block access rules? -

i developing new block. added it's instance page, there 2 problems:

1. after turn editing off disappear.
2. after logging out user disappear. think problem related db/access.php

i block sticky shown every body: users, guests, etc. how can solve problem?

the problem block should return contents. empty content results in disappearing block non-admin users! there no relation between question , db/access.php file!