Description of problem:
I got into firewalld from the GUI. After giving the root password I started looking at the various settings, being very careful not to click on or change anything. All of a sudden this bug occurred. 

Version-Release number of selected component:
firewall-config-0.3.12-1.fc21

Additional info:
reporter:       libreport-2.3.0
cmdline:        /usr/bin/python -Es /usr/bin/firewall-config
executable:     /usr/bin/firewall-config
kernel:         3.17.7-300.fc21.x86_64
runlevel:       N 5
type:           Python
uid:            1000

Truncated backtrace:
firewall-config:2087:onChangeZone:TypeError: 'NoneType' object is not iterable

Traceback (most recent call last):
  File "/usr/bin/firewall-config", line 2087, in onChangeZone
    for item in rules:
TypeError: 'NoneType' object is not iterable

Local variables in innermost frame:
masquerade: False
name: 'time-exceeded'
_services: []
sources: []
default: False
_icmpblocks: []
interfaces: []
args: (<TreeSelection object at 0x7f547bfbcc30 (GtkTreeSelection at 0x14d0ba0)>,)
iter: None
self: <__main__.FirewallConfig object at 0x7f547c02ba10>
item: ['1025-65535', 'tcp']
builtin: False
icmpblocks: []
rules: None
services: ['dhcpv6-client', 'samba-client', 'ssh']
selected_zone: 'FedoraWorkstation'
ports: [['1025-65535', 'udp'], ['1025-65535', 'tcp']]
forward_ports: []