Here is the output in the console:

Traceback (most recent call last):
  File "/usr/lib/pymodules/python2.7/ajenti/plugins/dashboard/dash.py", line 128, in refresh
    config=widget['config'],
  File "/usr/lib/pymodules/python2.7/ajenti/api/__init__.py", line 91, in new
    return context.instantiate(cls, *args, **kwargs)
  File "/usr/lib/pymodules/python2.7/ajenti/plugins/__init__.py", line 202, in instantiate
    init(instance)
  File "/usr/lib/pymodules/python2.7/ajenti/plugins/dashboard/api.py", line 37, in init
    {'text': _('Cancel'), 'id': 'cancel'},
AttributeError: 'NoneType' object has no attribute 'buttons'
Traceback (most recent call last):
  File "/usr/lib/pymodules/python2.7/ajenti/plugins/dashboard/dash.py", line 128, in refresh
    config=widget['config'],
  File "/usr/lib/pymodules/python2.7/ajenti/api/__init__.py", line 91, in new
    return context.instantiate(cls, *args, **kwargs)
  File "/usr/lib/pymodules/python2.7/ajenti/plugins/__init__.py", line 202, in instantiate
    init(instance)
  File "/usr/lib/pymodules/python2.7/ajenti/plugins/dashboard/api.py", line 37, in init
    {'text': _('Cancel'), 'id': 'cancel'},
AttributeError: 'NoneType' object has no attribute 'buttons'
23.09.2014 06:05 main.py:244                   DEBUG [root] {'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/fw_conntrack-year.png': 0.002151012420654297, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/fw_forwarded_local-day.png': 0.0021538734436035156, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/irqstats-day.png': 0.0030519962310791016, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/vmstat-year.png': 0.005326986312866211, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/load-week.png': 0.0022649765014648438, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/diskstats_iops-month.png': 0.0020749568939208984, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/vmstat-week.png': 0.0034668445587158203, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/df_inode-month.png': 0.002456188201904297, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/df_inode-week.png': 0.0021820068359375, 'HTTP 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0.0021970272064208984, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/interrupts-week.png': 0.0020520687103271484, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/fw_conntrack-day.png': 0.002337932586669922, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/fail2ban-month.png': 0.008870124816894531, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/diskstats_utilization-day.png': 0.0015540122985839844, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/diskstats_utilization-year.png': 0.0020952224731445312, 'Handling updates': 0.0012900829315185547, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/exim_mailqueue-week.png': 0.0028541088104248047, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/cpu-month.png': 0.0022928714752197266, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/df_inode-year.png': 0.002118825912475586, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/fail2ban-year.png': 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0.0023970603942871094, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/irqstats-week.png': 0.002199888229370117, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/if_eth0-year.png': 0.0021009445190429688, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/open_files-week.png': 0.002307891845703125, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/exim_mailqueue-day.png': 0.00156402587890625, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/fw_forwarded_local-month.png': 0.0020987987518310547, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/df-day.png': 0.0049440860748291016, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/swap-day.png': 0.0020961761474609375, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/if_eth0-month.png': 0.002131938934326172, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/cpu-day.png': 0.002767801284790039, 'HTTP /ajenti:munin-proxy//hoster.net/myserver.hoster.net/forks-week.png': 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www-data is a system user and can not be there to select. I can only select root and nobody, www-data is not displayed.