Why does huponexit not work in the following?

Bash manual says > If the huponexit shell option has been set with shopt (see Section 4.3.2 [The Shopt Builtin], page 62), Bash sends a SIGHUP to all jobs when an interactive login shell exits. Why does huponexit not work in the following? In one interactive shell $ shopt -s huponexit $ sleep 4321 & 13816 $ exit Then in the other shell $ ps -j 13816 PID PGID SID TTY STAT TIME COMMAND 13816 13816 13728 ? S 0:00 sleep 4321 Thanks.