Open threads offline

### Your use case

#### What would you like to do?

Open threads when there is no connection to a server.

#### Why would you like to do it?

Sometimes it is useful to open a new branch in a conversation, and why not also do it when you are offline?
So everything gets send, once you are back online.

#### How would you like to achieve it?

-

### Have you considered any alternatives?

-

### Additional context

-

### Are you willing to provide a PR?

No