(Pdb) op_filter.__str__()
"(OR: ('eventmethod__method__name__icontains', u'F'), ('eventmethod__method__description__icontains', u'F'), ('eventcustom__custom__name__icontains', u'F'), ('eventcustom__custom__description__icontains', u'F'), ('eventmaintenance__maintenance__name__icontains', u'F'), ('eventmaintenance__maintenance__description__icontains', u'F'), ('eventchannel__eventfailure__failure__name__icontains', u'F'), ('eventchannel__eventfailure__failure__description__icontains', u'F'))"

(Pdb) event_descr_filter.__str__()
"(OR: ('eventmethod__description__icontains', u'F'), ('eventcustom__description__icontains', u'F'), ('eventmaintenance__description__icontains', u'F'), ('eventchannel__eventfailure__description__icontains', u'F'))"

Make inner joins (unexpected result: return no rows)
====================================================
(Pdb) e = op_filter | event_descr_filter
(Pdb) e.__str__()
"(OR: ('eventmethod__method__name__icontains', u'F'), ('eventmethod__method__description__icontains', u'F'), ('eventcustom__custom__name__icontains', u'F'), ('eventcustom__custom__description__icontains', u'F'), ('eventmaintenance__maintenance__name__icontains', u'F'), ('eventmaintenance__maintenance__description__icontains', u'F'), ('eventchannel__eventfailure__failure__name__icontains', u'F'), ('eventchannel__eventfailure__failure__description__icontains', u'F'), ('eventmethod__description__icontains', u'F'), ('eventcustom__description__icontains', u'F'), ('eventmaintenance__description__icontains', u'F'), ('eventchannel__eventfailure__description__icontains', u'F'))"

Make outer joins (what i was waiting for...)
============================================
(Pdb) e = event_descr_filter | op_filter
(Pdb) e.__str__()
"(OR: ('eventmethod__description__icontains', u'F'), ('eventcustom__description__icontains', u'F'), ('eventmaintenance__description__icontains', u'F'), ('eventchannel__eventfailure__description__icontains', u'F'), ('eventmethod__method__name__icontains', u'F'), ('eventmethod__method__description__icontains', u'F'), ('eventcustom__custom__name__icontains', u'F'), ('eventcustom__custom__description__icontains', u'F'), ('eventmaintenance__maintenance__name__icontains', u'F'), ('eventmaintenance__maintenance__description__icontains', u'F'), ('eventchannel__eventfailure__failure__name__icontains', u'F'), ('eventchannel__eventfailure__failure__description__icontains', u'F'))"



OR filters side by side
=======================

"(OR: ('eventmethod__method__name__icontains',
 u'F'),
 ('eventmethod__method__description__icontains',
 u'F'),
 ('eventcustom__custom__name__icontains',
 u'F'),
 ('eventcustom__custom__description__icontains',
 u'F'),
 ('eventmaintenance__maintenance__name__icontains',
 u'F'),
 ('eventmaintenance__maintenance__description__icontains',
 u'F'),
 ('eventchannel__eventfailure__failure__name__icontains',
 u'F'),
 ('eventchannel__eventfailure__failure__description__icontains',
 u'F'),
 ('eventmethod__description__icontains',
 u'F'),
 ('eventcustom__description__icontains',
 u'F'),
 ('eventmaintenance__description__icontains',
 u'F'),
 ('eventchannel__eventfailure__description__icontains',
 u'F'))"

"(OR: ('eventmethod__description__icontains',
 u'F'),
 ('eventcustom__description__icontains',
 u'F'),
 ('eventmaintenance__description__icontains',
 u'F'),
 ('eventchannel__eventfailure__description__icontains',
 u'F'),
 ('eventmethod__method__name__icontains',
 u'F'),
 ('eventmethod__method__description__icontains',
 u'F'),
 ('eventcustom__custom__name__icontains',
 u'F'),
 ('eventcustom__custom__description__icontains',
 u'F'),
 ('eventmaintenance__maintenance__name__icontains',
 u'F'),
 ('eventmaintenance__maintenance__description__icontains',
 u'F'),
 ('eventchannel__eventfailure__failure__name__icontains',
 u'F'),
 ('eventchannel__eventfailure__failure__description__icontains',
 u'F'))"
