diff --git a/helpdesk/query.py b/helpdesk/query.py
index 9ae9e400..9c5a0930 100644
--- a/helpdesk/query.py
+++ b/helpdesk/query.py
@@ -28,14 +28,18 @@ def query_from_base64(b64data):
 
 
 def get_search_filter_args(search):
+    if not search:
+        return Q()
     if search.startswith('queue:'):
         return Q(queue__title__icontains=search[len('queue:'):])
     if search.startswith('priority:'):
         return Q(priority__icontains=search[len('priority:'):])
-    filter = Q()
+    my_filter = Q()
     for subsearch in search.split("OR"):
         subsearch = subsearch.strip()
-        filter = (
+        if not subsearch:
+            continue
+        my_filter = (
             filter |
             Q(id__icontains=subsearch) |
             Q(title__icontains=subsearch) |
@@ -48,7 +52,7 @@ def get_search_filter_args(search):
             Q(created__icontains=subsearch) |
             Q(due_date__icontains=subsearch)
         )
-    return filter
+    return my_filter
 
 
 DATATABLES_ORDER_COLUMN_CHOICES = Choices(
@@ -91,23 +95,49 @@ class __Query__:
 
     def __run__(self, queryset):
         """
-        Apply a dict-based set of filters & parameters to a queryset.
+        Apply a dict-based set of value_filters & parameters to a queryset.
 
         queryset is a Django queryset, eg MyModel.objects.all() or
             MyModel.objects.filter(user=request.user)
 
         params is a dictionary that contains the following:
-           filtering: A dict of Django ORM filters, eg:
+           filtering: A dict of Django ORM value_filters, eg:
             {'user__id__in': [1, 3, 103], 'title__contains': 'foo'}
 
         search_string: A freetext search string
 
         sorting: The name of the column to sort by
         """
-        filter = self.params.get('filtering', {})
-        filter_or = self.params.get('filtering_or', {})
+        q_args = []
+        value_filters = self.params.get('filtering', {})
+        null_filters = self.params.get('filtering_null', {})
+        if null_filters:
+            if value_filters:
+                # Check if any of the value value_filters are for the same field as the
+                # ISNULL filter so that an OR filter can be set up
+                matched_null_keys = []
+                for null_key in null_filters:
+                    field_path = null_key[:-8] # Chop off the "__isnull"
+                    matched_key = None
+                    for val_key in value_filters:
+                        if val_key.startswith(field_path):
+                            matched_key = val_key
+                            break
+                    if matched_key:
+                        # Remove the matching filters into a Q param
+                        matched_null_keys.append(null_key)
+                        # Create an OR query for the selected value(s) OR if the field is NULL
+                        v = {}
+                        v[val_key] = value_filters[val_key]
+                        n = {}
+                        n[null_key] = null_filters[null_key]
+                        q_args.append((Q(**v) | Q(**n)))
+                        del value_filters[matched_key]
+                # Now remove the matched null keys
+                for null_key in matched_null_keys:
+                    del null_filters[null_key]
         queryset = queryset.filter(
-            (Q(**filter) | Q(**filter_or)) & self.get_search_filter_args())
+            *q_args, (Q(**value_filters) & Q(**null_filters)) & self.get_search_filter_args())
         sorting = self.params.get('sorting', None)
         if sorting:
             sortreverse = self.params.get('sortreverse', None)
diff --git a/helpdesk/templates/helpdesk/filters/kbitems.html b/helpdesk/templates/helpdesk/filters/kbitems.html
index 17cab5f7..87316fea 100644
--- a/helpdesk/templates/helpdesk/filters/kbitems.html
+++ b/helpdesk/templates/helpdesk/filters/kbitems.html
@@ -8,7 +8,7 @@
     <div class="col col-sm-3">
         <select id='id_kbitems' name='kbitem' multiple='selected' size='5'>
             {% with magic_number=-1 %}
-            <option value='{{magic_number}}'{% if magic_number|in_list:query_params.filtering.kbitem__in %} selected='selected'{% endif %}>
+            <option value='{{magic_number}}'{% if query_params.filtering_null.kbitem__isnull %} selected='selected'{% endif %}>
                 {% trans "Uncategorized" %}
             </option>
             {% endwith %}
diff --git a/helpdesk/templates/helpdesk/filters/owner.html b/helpdesk/templates/helpdesk/filters/owner.html
index 87e5bfad..6e1335e7 100644
--- a/helpdesk/templates/helpdesk/filters/owner.html
+++ b/helpdesk/templates/helpdesk/filters/owner.html
@@ -8,7 +8,7 @@
     <div class="col col-sm-3">
         <select id='id_owners' name='assigned_to' multiple='selected' size='5'>
             {% with magic_number=-1 %}
-            <option value='{{magic_number}}'{% if magic_number|in_list:query_params.filtering.assigned_to__id__in %} selected='selected'{% endif %}>
+            <option value='{{magic_number}}'{% if query_params.filtering_null.assigned_to__id__isnull %} selected='selected'{% endif %}>
                 {% trans "Unassigned" %}
             </option>
             {% endwith %}
diff --git a/helpdesk/templates/helpdesk/filters/queue.html b/helpdesk/templates/helpdesk/filters/queue.html
index dd66d53d..4f3b3334 100644
--- a/helpdesk/templates/helpdesk/filters/queue.html
+++ b/helpdesk/templates/helpdesk/filters/queue.html
@@ -7,6 +7,11 @@
     </div>
     <div class="col col-sm-3">
         <select id='id_queues' name='queue' multiple='selected' size='5'>
+          {% with magic_number=-1 %}
+            <option value='{{magic_number}}'{% if query_params.filtering_null.queue__id__isnull %} selected='selected'{% endif %}>
+                {% trans "Unassigned" %}
+            </option>
+          {% endwith %}
           {% for q in queue_choices %}
             <option value='{{ q.id }}'{% if q.id|in_list:query_params.filtering.queue__id__in %} selected="selected"{% endif %}>{{ q.title }}</option>
             {% endfor %}
diff --git a/helpdesk/templates/helpdesk/ticket_list.html b/helpdesk/templates/helpdesk/ticket_list.html
index c511d5f2..2e644c7f 100644
--- a/helpdesk/templates/helpdesk/ticket_list.html
+++ b/helpdesk/templates/helpdesk/ticket_list.html
@@ -170,10 +170,10 @@
                                         <option id="filterBuilderSelect-Sort" value="Sort"{% if query_params.sorting %} disabled{% endif %}>
                                             {% trans "Sorting" %}
                                         </option>
-                                        <option id="filterBuilderSelect-Owner" value="Owner"{% if query_params.filtering.assigned_to__id__in %} disabled{% endif %}>
+                                        <option id="filterBuilderSelect-Owner" value="Owner"{% if query_params.filtering.assigned_to__id__in or query_params.filtering_null.assigned_to__id__isnull %} disabled{% endif %}>
                                             {% trans "Owner" %}
                                         </option>
-                                        <option id="filterBuilderSelect-Queue" value="Queue"{% if query_params.filtering.queue__id__in %} disabled{% endif %}>
+                                        <option id="filterBuilderSelect-Queue" value="Queue"{% if query_params.filtering.queue__id__in or query_params.filtering_null.queue__id__isnull %} disabled{% endif %}>
                                             {% trans "Queue" %}
                                         </option>
                                         <option id="filterBuilderSelect-Status" value="Status"{% if query_params.filtering.status__in %} disabled{% endif %}>
@@ -185,7 +185,7 @@
                                         <option id="filterBuilderSelect-Dates" value="Dates"{% if query_params.filtering.created__gte or query_params.filtering.created__lte %} disabled{% endif %}>
                                             {% trans "Date Range" %}
                                         </option>
-                                        <option id="filterBuilderSelect-KBItems" value="KBItems"{% if query_params.filtering.kbitem__in %} disabled{% endif %}>
+                                        <option id="filterBuilderSelect-KBItems" value="KBItems"{% if query_params.filtering.kbitem__in or query_params.filtering_null.kbitem__isnull %} disabled{% endif %}>
                                             {% trans "Knowledge base items" %}
                                         </option>
                                     </select>
@@ -200,11 +200,11 @@
                                     id="filterBoxSort">
                                     {% include 'helpdesk/filters/sorting.html' %}
                                 </li>
-                                <li class="filterBox{% if query_params.filtering.assigned_to__id__in %} filterBoxShow{% endif %} list-group-item"
+                                <li class="filterBox{% if query_params.filtering.assigned_to__id__in or query_params.filtering_null.assigned_to__id__isnull %} filterBoxShow{% endif %} list-group-item"
                                     id=filterBoxOwner>
                                     {% include 'helpdesk/filters/owner.html' %}
                                 </li>
-                                <li class="list-group-item filterBox{% if query_params.filtering.queue__id__in %} filterBoxShow{% endif %}"
+                                <li class="list-group-item filterBox{% if query_params.filtering.queue__id__in or query_params.filtering_null.queue__id__isnull %} filterBoxShow{% endif %}"
                                     id="filterBoxQueue">
                                     {% include 'helpdesk/filters/queue.html' %}
                                 </li>
@@ -220,7 +220,7 @@
                                     id="filterBoxKeywords">
                                     {% include 'helpdesk/filters/keywords.html' %}
                                 </li>
-                                <li class="list-group-item filterBox{% if query_params.filtering.kbitem__in %} filterBoxShow{% endif %}"
+                                <li class="list-group-item filterBox{% if query_params.filtering.kbitem__in or query_params.filtering_null.kbitem__isnull %} filterBoxShow{% endif %}"
                                     id="filterBoxKBItems">
                                     {% include 'helpdesk/filters/kbitems.html' %}
                                 </li>
diff --git a/helpdesk/tests/test_query.py b/helpdesk/tests/test_query.py
index bee5b664..f86faf55 100644
--- a/helpdesk/tests/test_query.py
+++ b/helpdesk/tests/test_query.py
@@ -8,6 +8,7 @@ from helpdesk.tests.helpers import get_staff_user
 
 class QueryTests(TestCase):
     def setUp(self):
+        # self.maxDiff = None
         self.queue = Queue.objects.create(
             title="Test queue",
             slug="test_queue",
@@ -94,7 +95,7 @@ class QueryTests(TestCase):
     def test_query_by_no_kbitem(self):
         self.loginUser()
         query = query_to_base64(
-            {'filtering_or': {'kbitem__in': [self.kbitem1.pk]}}
+            {'filtering_null': {'kbitem__isnull': True}}
         )
         response = self.client.get(
             reverse('helpdesk:datatables_ticket_list', args=[query]))
@@ -103,8 +104,8 @@ class QueryTests(TestCase):
             resp_json,
             {
                 "data":
-                [{"ticket": "2 [test_queue-2]", "id": 2, "priority": 3, "title": "assigned to kbitem", "queue": {"title": "Test queue", "id": 1}, "status": "Open",
-                    "created": resp_json["data"][0]["created"], "due_date": None, "assigned_to": "None", "submitter": None, "row_class": "", "time_spent": "", "kbitem": "KBItem 1"}],
+                [{"ticket": "1 [test_queue-1]", "id": 1, "priority": 3, "title": "unassigned to kbitem", "queue": {"title": "Test queue", "id": 1}, "status": "Open",
+                    "created": resp_json["data"][0]["created"], "due_date": None, "assigned_to": "None", "submitter": None, "row_class": "", "time_spent": "", "kbitem": ""}],
                 "recordsFiltered": 1,
                 "recordsTotal": 1,
                 "draw": 0,
diff --git a/helpdesk/views/staff.py b/helpdesk/views/staff.py
index fb6104c0..89aea899 100644
--- a/helpdesk/views/staff.py
+++ b/helpdesk/views/staff.py
@@ -991,7 +991,7 @@ def ticket_list(request):
     # a query, to be saved if needed:
     query_params = {
         'filtering': {},
-        'filtering_or': {},
+        'filtering_null': {},
         'sorting': None,
         'sortreverse': False,
         'search_string': '',
@@ -1035,12 +1035,20 @@ def ticket_list(request):
         for param, filter_command in filter_in_params:
             if request.GET.get(param) is not None:
                 patterns = request.GET.getlist(param)
+                if not patterns:
+                    continue
+                try:
+                    minus_1_ndx = patterns.index("-1")
+                    # Must have the value so remove it and configure to use OR filter on NULL
+                    patterns.pop(minus_1_ndx)
+                    query_params['filtering_null'][filter_null_params[param]] = True
+                except ValueError:
+                    pass
+                if not patterns:
+                    # Caters for the case where the filter is only a null filter
+                    continue
                 try:
                     pattern_pks = [int(pattern) for pattern in patterns]
-                    if -1 in pattern_pks:
-                        query_params['filtering_or'][filter_null_params[param]] = True
-                    else:
-                        query_params['filtering_or'][filter_command] = pattern_pks
                     query_params['filtering'][filter_command] = pattern_pks
                 except ValueError:
                     pass
diff --git a/setup.py b/setup.py
index 240d9c85..f725b138 100644
--- a/setup.py
+++ b/setup.py
@@ -6,7 +6,7 @@ from setuptools import find_packages, setup
 import sys
 
 
-version = '1.3.0'
+version = '1.3.1'
 
 
 # Provided as an attribute, so you can append to these instead