Killing all emacsclients in X11 shuts down emacs server

[Thorsten]

Hi List, 
when I run one emacs daemon and several emacsclients in 2 sessions
(terminal and X11) I encounter the following inconvenience: 

I have several emacsclient windors open in my tmux terminal session, and
just a few (lets say 2) in my X11 session. When I'm done in X11, I close
both buffers with C-x # and go back to the terminal session. 
But then emacs daemon has died, although there should be more active
buffers in the terminal session. 

I then have to start emacsd again and set up all muy emacsclient windows
in the terminal session again, although I really just wanted to kill the
2 buffers in the X11 session and continue working in the terminal
session. 

Is that a known behaviour - killing the last emacsclient buffer in one
session kills the emacs daemon, although there are open emacsclient
buffers in another session?

-- 
cheers,
Thorsten