Why wpa_supplicant doesn't get new ip when reassociate?

Question

/etc/network/interfaces:

auto wlan0
iface wlan0 inet dhcp
wpa-conf /etc/wpa_supplicant.conf

/etc/wpa_supplicant.conf

update_config=1
ctrl_interface=DIR=/var/run/wpa_supplicant

network={
        ssid="DIANA"
        psk=some_hashed_psk
        priority=100
        id_str="home"
}
network={
        ssid="ALEX"
        psk=some_hashed_psk
        priority=1000
        id_str="work"
}

Hi there, the question is: How to make wpa_supplicant renew the IP address when device connects to another wi-fi access point? If I manually run dhclient wlan0 - it renews IP and all ok. But I must do it automatically after reconnect to another wi-fo spot.

I read about roaming but it doesn't the trick. I hoped on /sbin/wpa_action but it don't runs too, I placed post-up hook on interface, but wpa_supplicant even doesn't down/up it.

OS: Ubuntu linux