Background job started from .bashrc is killed by ctrl-z from prompt

[cetteadressemail]

Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='x86_64'
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='x86_64-unknown-linux-gnu'
-DCONF_VENDOR='unknown' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL
-DHAVE_CONFIG_H   -I.  -I. -I./include -I./lib   -march=x86-64 -mtune=generic
-O2 -pipe -fstack-protector --param=ssp-buffer-size=4 -D_FORTIFY_SOURCE=2
-DDEFAULT_PATH_VALUE='/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin'
-DSTANDARD_UTILS_PATH='/usr/bin:/bin:/usr/sbin:/sbin'
-DSYS_BASHRC='/etc/bash.bashrc' -DSYS_BASH_LOGOUT='/etc/bash.bash_logout'
uname output: Linux localhost 3.8.10-1-ARCH #1 SMP PREEMPT Sat Apr 27 12:36:59
CEST 2013 x86_64 GNU/Linux
Machine Type: x86_64-unknown-linux-gnu

Bash Version: 4.2
Patch Level: 45
Release Status: release

Description:
        I know this is something odd to do, I would like to start my windows 
manager
from .bashrc.
        If I do so and hit ctrl-z while bash is asking me for command line, the 
job is
suspended.
        I can't resume it : "bash: bg: job 1 started without job control"


Repeat-By:
        echo "sleep 10" >> /tmp/bashrc
        bash --rcfile /tmp/bashrc
        [hit ctrl-z]

Fix:
        Do not use .bashrc as it !