diff --git a/src/postorius/forms.py b/src/postorius/forms.py
index 6fd6872..a264266 100644
--- a/src/postorius/forms.py
+++ b/src/postorius/forms.py
@@ -57,6 +57,21 @@
         return result
 
 
+class NullBooleanRadioSelect(forms.RadioSelect):
+    """
+    This is necessary to detect that such a field has not been changed.
+    """
+
+    def value_from_datadict(self, data, files, name):
+        value = data.get(name, None)
+        return {'2': True,
+                True: True,
+                'True': True,
+                '3': False,
+                'False': False,
+                False: False}.get(value, None)
+
+
 class SiteModelChoiceField(forms.ModelChoiceField):
 
     def label_from_instance(self, obj):
@@ -774,7 +789,7 @@
             'preferred, but if you have a problem reading them, select '
             'plain text digests.'))
     receive_own_postings = forms.NullBooleanField(
-        widget=forms.RadioSelect(choices=choices),
+        widget=NullBooleanRadioSelect(choices=choices),
         required=False,
         label=_('Receive own postings'),
         help_text=_(
@@ -783,13 +798,13 @@
             'to No.'
             ))
     acknowledge_posts = forms.NullBooleanField(
-        widget=forms.RadioSelect(choices=choices),
+        widget=NullBooleanRadioSelect(choices=choices),
         required=False,
         label=_('Acknowledge posts'),
         help_text=_(
             'Receive acknowledgement mail when you send mail to the list?'))
     hide_address = forms.NullBooleanField(
-        widget=forms.RadioSelect(choices=choices),
+        widget=NullBooleanRadioSelect(choices=choices),
         required=False,
         label=_('Hide address'),
         help_text=_(
@@ -799,7 +814,7 @@
             'If you do not want your email address to show up on this '
             'membership roster at all, select Yes for this option.'))
     receive_list_copy = forms.NullBooleanField(
-        widget=forms.RadioSelect(choices=choices),
+        widget=NullBooleanRadioSelect(choices=choices),
         required=False,
         label=_('Avoid Duplicates'),
         help_text=_(