1. don't apply this patch
2. login to the Admin Console
3. enable to `DBG_REDIRECT` in the `/system/debug.php` (assuming, that Debug Mode is enabled as well)
4. press the `Logout` link in the top frame
5. confirm, this SQL is present in the Debugger Report:
```
lang=sql
DELETE FROM 52x_UserSessionData
WHERE SessionId = '' AND VariableName = 'priority_deleted';
```
6. click on the link, that `DBG_REDIRECT` shown instead of a page content
7. confirm, that the Admin Login page is displayed
8. apply the patch
9. login to the Admin Console (click on the any `DBG_REDIRECT` shown links as needed)
10. press the `Logout` link in the top frame
11. confirm, that SQL, that removes the `priority_deleted` session variable has disappeared