"This is a notice to all users" check box doesn't work for private messages


If you send a private message to a user and activate the checkbox "This is a notice to all users", instead of sending a private message the system send a kind of sticky notice to all users. In the default buddy press theme you can see something similar to a post-it in the right sidebar (see attachment).

Using the BuddyPress Fun theme, there is no such notice. Isn't it active? Any way to activate it? It's really helpful.

Thanks in advance.