Description of problem:
Right after I selected a language to use, anaconda showed window with network setting. 

I have turned on network (wired). 

On the main window of anaconda there was something like 'unset installation source' (I used netinst.iso). 

I clicked on Installation source and on 'done'. 

Installation source was set up now but no 'software collection' was chosen. 

When I clicked on 'Software selection' the anaconda froze and traceback was shown.
The following was filed automatically by anaconda:
anaconda 19.25-1 exception report
Traceback (most recent call first):
  File "/usr/lib/python2.7/site-packages/yum/comps.py", line 669, in return_environments
    for item in env_pattern.split(','):
  File "/usr/lib/python2.7/site-packages/yum/comps.py", line 650, in has_environment
    exists = self.return_environments(environmentid)
  File "/usr/lib64/python2.7/site-packages/pyanaconda/packaging/yumpayload.py", line 1084, in environmentGroups
    if not groups.has_environment(environmentid):
  File "/usr/lib64/python2.7/site-packages/pyanaconda/ui/gui/spokes/software.py", line 337, in on_environment_toggled
    for groupid in self.payload.environmentGroups(self.environment):
  File "/usr/lib64/python2.7/site-packages/pyanaconda/ui/gui/spokes/software.py", line 353, in on_environment_selection_changed
    self.on_environment_toggled(None, model.get_path(itr))
AttributeError: 'NoneType' object has no attribute 'split'

Version-Release number of selected component:
anaconda-19.25-1

Additional info:
cmdline:        /usr/bin/python  /sbin/anaconda
cmdline_file:   BOOT_IMAGE=/images/pxeboot/vmlinuz inst.stage2=hd:LABEL=Fedora\x2019-Beta-TC4\x20x86_64 quiet
executable:     /sbin/anaconda
hashmarkername: anaconda
kernel:         3.9.0-301.fc19.x86_64
product:        Fedora
release:        Cannot get release name.
type:           anaconda
version:        19-Beta-TC4

Truncated backtrace:
Traceback (most recent call last):
  File "/usr/lib64/python2.7/site-packages/pyanaconda/ui/gui/spokes/software.py", line 353, in on_environment_selection_changed
    self.on_environment_toggled(None, model.get_path(itr))
  File "/usr/lib64/python2.7/site-packages/pyanaconda/ui/gui/spokes/software.py", line 337, in on_environment_toggled
    for groupid in self.payload.environmentGroups(self.environment):
  File "/usr/lib64/python2.7/site-packages/pyanaconda/packaging/yumpayload.py", line 1084, in environmentGroups
    if not groups.has_environment(environmentid):
  File "/usr/lib/python2.7/site-packages/yum/comps.py", line 650, in has_environment
    exists = self.return_environments(environmentid)
  File "/usr/lib/python2.7/site-packages/yum/comps.py", line 669, in return_environments
    for item in env_pattern.split(','):
AttributeError: 'NoneType' object has no attribute 'split'