mail message not deleted from inbox even when flagged as DELETED (nuxeo-platform-mail-core)

when using addon nuxeo-platform-mail-core, mail messages are never removed from mail inbox even when mail message flag is set to DELETED (done by a new MessageAction). Class MailBoxActionsImpl needs a few modification to achieve deletion. The reason is that mailbox folder is open in READONLY mode. Here is the new constructor :
public MailBoxActionsImpl(Folder folder, boolean expungeOnExit)
throws MessagingException {
this.folder = folder;
if (expungeOnExit)

{ folder.open(Folder.READ_WRITE); }

else

{ folder.open(Folder.READ_ONLY); }

expunge = expungeOnExit;
}