943 release openhelpermanager

Implement #943 issue.

Please review my code. Thx!
It is not a question of "habit". If the reference cannot be null, it is
absolutely unnecessary to use a null check. If the reference can be null,
you must add a null check. Actually you even get warnings if you use
`@Nullable`/`@NotNull` annotations and a static analysis tool which
inspects them.