can not connect to hidden wifi without certificate after upgrade

[Qu Bit]

when trying to connect to a hidden corporate WLAN network the connection can not be established.
it seems to be a problem in the authentication procedure

1)
Description: Ubuntu 15.04
Release: 15.04
Linux odysseus 3.13.0-43-generic #72-Ubuntu SMP Mon Dec 8 19:35:06 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

computer:
DELL LATITUDE E6430

wifi module:
iwlwifi 3.13.0-43-generic SMP mod_unload modversions

02:00.0 Network controller: Intel Corporation Centrino Ultimate-N 6300 (rev 35)
        Subsystem: Intel Corporation Centrino Ultimate-N 6300 3x3 AGN
        Kernel driver in use: iwlwifi

2)
network-manager-gnome:
  Installed: 0.9.10.1-0ubuntu4
  Candidate: 0.9.10.1-0ubuntu4
  Version table:
 *** 0.9.10.1-0ubuntu4 0
        500 http://at.archive.ubuntu.com/ubuntu/ vivid/main amd64 Packages
        100 /var/lib/dpkg/status

connection settings:
(/etc/NetworkManager/system-connections/wlan_myssid)
'
[wifi-security]
key-mgmt=wpa-eap

[connection]
id=wlan_myssid
uuid=41b56668-e384-FFFF-FFFF-b4df161778ae
type=wifi
permissions=user:jdoe:;
autoconnect=false

[ipv6]
method=auto
ip6-privacy=0

[wifi]
ssid=wlan_ssid
mode=infrastructure
mac-address=FF:FF:FF:FF:FF:FF
security=802-11-wireless-security
hidden=true

[802-1x]
eap=peap;
identity=Domain\\DoeJ
phase2-auth=mschapv2
password-flags=3

[ipv4]
method=auto
'

3)
i expect it to connect.

4)
nm hangs in the trying-to-connect procedure (bradcasting wifi symbol)
asking for entering the password from time to time.

REMARKS:
exact same settings
* worked on same machine and
* do work on another machine under Ubuntu 14.10

before 15.04 the nm allowed to leave out the certeficate (None) and NOT check the box for "no certificate is required" when saving the connection data
thus leading to a question upon authentication attempt allowing to "ignore" that there is no certificate.

this might just be the time delay required for things to work.