diff --git a/web_advanced_filters/model/ir_filters.py b/web_advanced_filters/model/ir_filters.py
index fb09d45b..72c7a958 100644
--- a/web_advanced_filters/model/ir_filters.py
+++ b/web_advanced_filters/model/ir_filters.py
@@ -27,6 +27,7 @@ from openerp.tools.translate import _
 
 class IrFilters(Model):
     _inherit = 'ir.filters'
+    _evaluate_before_negate = ['one2many', 'many2many']
 
     def _is_frozen_get(self, cr, uid, ids, field_name, args, context=None):
         '''determine if this is fixed list of ids'''
@@ -65,17 +66,60 @@ class IrFilters(Model):
                     cr, uid, this['union_filter_ids'], ['domain'],
                     context=context)])
             for c in self.read(cr, uid, this['complement_filter_ids'],
-                               ['domain'], context=context):
-                domain = expression.AND([
-                    domain,
-                    ['!'] + eval_n(c['domain'])])
-            result[this['id']] = str(domain)
+                               ['domain', 'evaluate_before_negate',
+                                'model_id'],
+                               context=context):
+                if c['evaluate_before_negate']:
+                    matching_ids = self.pool[c['model_id']].search(
+                        cr, uid, eval_n(c['domain']),
+                        context=context)
+                    domain = expression.AND([
+                        domain,
+                        [('id', 'not in', matching_ids)],
+                    ])
+                else:
+                    domain = expression.AND([
+                        domain,
+                        ['!'] + eval_n(c['domain'])])
+            result[this['id']] = str(expression.normalize_domain(domain))
         return result
 
     def _domain_set(self, cr, uid, ids, field_name, field_value, args,
                     context=None):
         self.write(cr, uid, ids, {'domain_this': field_value})
 
+    def _evaluate_before_negate_get(self, cr, uid, ids, field_name, args,
+                                    context=None):
+        """check if this filter contains references to x2many fields. If so,
+        then negation goes wrong in nearly all cases, so we evaluate the
+        filter and remove its resulting ids"""
+        result = {}
+        for this in self.read(cr, uid, ids, ['model_id', 'domain'],
+                              context=context):
+            result[this['id']] = False
+            complement_domain = expression.normalize_domain(
+                safe_eval(this['domain'] or 'False') or
+                [expression.FALSE_LEAF])
+            for arg in complement_domain:
+                if not expression.is_leaf(arg):
+                    continue
+                current_model = self.pool.get(this['model_id'])
+                if not current_model:
+                    continue
+                has_x2many = False
+                for field_name in arg[0].split('.'):
+                    field = current_model._all_columns[field_name].column
+                    has_x2many |= field._type in self._evaluate_before_negate
+                    has_x2many |= isinstance(field, fields.function)
+                    if hasattr(field, '_obj'):
+                        current_model = self.pool.get(field._obj)
+                    if not current_model or has_x2many:
+                        break
+                if has_x2many:
+                    result[this['id']] = True
+                    break
+        return result
+
     _columns = {
         'is_frozen': fields.function(
             _is_frozen_get, type='boolean', string='Frozen'),
@@ -93,6 +137,11 @@ class IrFilters(Model):
             fnct_inv=_domain_set),
         'domain_this': fields.text(
             'This filter\'s own domain', oldname='domain'),
+        'evaluate_before_negate': fields.function(
+            _evaluate_before_negate_get, type='boolean',
+            string='Evaluate this filter before negating',
+            help='This is necessary if this filter contains positive operators'
+            'on x2many fields')
     }
 
     _defaults = {
@@ -140,7 +189,7 @@ class IrFilters(Model):
                 'res_model': this.model_id,
                 'domain': this.domain,
                 'view_type': 'form',
-                'view_mode': 'tree',
+                'view_mode': 'tree,form',
                 'context': {
                     'default_filter_id': this.id,
                 },
diff --git a/web_advanced_filters/view/ir_filters.xml b/web_advanced_filters/view/ir_filters.xml
index 057db6b1..32c562e6 100644
--- a/web_advanced_filters/view/ir_filters.xml
+++ b/web_advanced_filters/view/ir_filters.xml
@@ -21,6 +21,12 @@
                         <field name="complement_filter_ids" nolabel="1" domain="[('user_id', 'in', [False, uid]),('id', '!=', id), ('model_id', '=', model_id)]" />
                     </group>
                 </group>
+                <field name="domain" position="attributes">
+                    <attribute name="attrs">{'readonly': ['|', ('union_filter_ids', '!=', [[6, False, []]]), ('complement_filter_ids', '!=', [[6, False, []]])]}</attribute>
+                </field>
+                <field name="domain" position="after">
+                    <field name="domain_this" attrs="{'invisible': [('union_filter_ids', '=', [[6, False, []]]), ('complement_filter_ids', '=', [[6, False, []]])]}" />
+                </field>
             </field>
         </record>
         <record id="form_ir_filters_save_new" model="ir.ui.view">