SnippetCmsGroupForm should not clean previous permissions

kfet/cms/forms.py

@@ -62,6 +62,8 @@ class SnippetsCmsGroupForm(KeepUnselectableModelFormMixin, forms.ModelForm):
         queryset=Permission.kfetcms.all(),
     )
 
+    keep_unselectable_fields = ['permissions']
+
     class Meta:
         model = Group
         fields = ('permissions',)