diff --git a/work_type.py b/work_type.py
index e6810935e4..e7af891985 100644
--- a/work_type.py
+++ b/work_type.py
@@ -15,6 +15,7 @@ class WorkType(OSV):
     active = fields.Boolean('Active')
     parent = fields.Many2One('timesheet.work_type', 'Parent', select=2)
     childs = fields.One2Many('timesheet.work_type', 'parent', 'Childs')
+    hours = fields.Function('get_hours', digits=(16, 2), string='Hours')
     type = fields.Selection([
         ('view', 'View'),
         ('normal', 'Normal'),
@@ -37,6 +38,45 @@ class WorkType(OSV):
         res = self.name_get(cursor, user, ids, context=context)
         return dict(res)
 
+
+    def _tree_qty(self, hours_by_wt, childs, ids, to_compute):
+        res = 0
+        for h in ids:
+            if (not childs.get(h)) or (not to_compute[h]):
+                res += hours_by_wt.setdefault(h, 0)
+            else:
+                sub_qty = self._tree_qty(
+                    hours_by_wt, childs, childs[h], to_compute)
+                hours_by_wt.setdefault(h, 0)
+                hours_by_wt[h] += sub_qty
+                res += hours_by_wt[h]
+                to_compute[h] = False
+        return res
+
+    def get_hours(self, cursor, user, ids, name, arg, context=None):
+        all_ids = self.search(cursor, user, [('parent', 'child_of', ids)])
+        clause = "SELECT work_type, sum(hours) FROM timesheet_line "\
+                     "WHERE work_type IN (%s) "\
+                     % ",".join(["%s" for id in all_ids])
+        date_cond = ""
+        if context.get('from_date'):
+            date_cond = " AND date >= '%s'"% str(context.get('from_date'))
+        if context.get('to_date'):
+            date_cond += " AND date <= '%s'"% str(context.get('to_date'))
+        clause += date_cond + " GROUP BY work_type"
+
+        cursor.execute(clause, all_ids)
+
+        hours_by_wt = dict([(i[0], i[1]) for i in cursor.fetchall()])
+        to_compute = dict.fromkeys(all_ids, True)
+        work_types = self.browse(cursor, user, all_ids, context=context)
+        childs = {}
+        for work_type in work_types:
+            if work_type.parent:
+                childs.setdefault(work_type.parent.id, []).append(work_type.id)
+        self._tree_qty(hours_by_wt, childs, ids, to_compute)
+        return hours_by_wt
+
     def name_get(self, cursor, user, ids, context=None):
         if not ids:
             return []
@@ -67,3 +107,55 @@ class WorkType(OSV):
         return res
 
 WorkType()
+
+
+
+
+class OpenWorkTypeInit(WizardOSV):
+    _name = 'timesheet.work_type.open.init'
+    from_date = fields.Date('From Date')
+    to_date = fields.Date('To Date')
+OpenWorkTypeInit()
+
+
+class OpenWorkType(Wizard):
+    'Open Work Types'
+    _name = 'timesheet.work_type.open'
+    states = {
+        'init': {
+            'result': {
+                'type': 'form',
+                'object': 'timesheet.work_type.open.init',
+                'state': [
+                    ('end', 'Cancel', 'gtk-cancel'),
+                    ('open', 'Open', 'gtk-ok', True),
+                ],
+            },
+        },
+        'open': {
+            'result': {
+                'type': 'action',
+                'action': '_action_open_work_type',
+                'state': 'end',
+            },
+        },
+    }
+
+    def _action_open_work_type(self, cursor, user, data, context=None):
+        model_data_obj = self.pool.get('ir.model.data')
+        act_window_obj = self.pool.get('ir.action.act_window')
+
+        model_data_ids = model_data_obj.search(cursor, user, [
+            ('fs_id', '=', 'act_work_type_tree2'),
+            ('module', '=', 'timesheet'),
+            ], limit=1, context=context)
+        model_data = model_data_obj.browse(cursor, user, model_data_ids[0],
+                context=context)
+        res = act_window_obj.read(cursor, user, model_data.db_id, context=context)
+        res['context'] = str({
+            'from_date': data['form']['from_date'],
+            'to_date': data['form']['to_date'],
+            })
+        return res
+
+OpenWorkType()
diff --git a/work_type.xml b/work_type.xml
index 4ca1390bd2..3a2bfe29ca 100644
--- a/work_type.xml
+++ b/work_type.xml
@@ -80,6 +80,41 @@
         </record>
         <menuitem parent="menu_work_type_form" action="act_work_type_tree"
             id="menu_work_type_tree"/>
+
+        <record model="ir.ui.view" id="work_type_view_tree3">
+            <field name="model">timesheet.work_type</field>
+            <field name="type">tree</field>
+            <field name="priority" eval="16"/>
+            <field name="field_childs">childs</field>
+            <field name="arch" type="xml">
+                <![CDATA[
+                <tree string="Work Types">
+                    <field name="name" select="1"/>
+                    <field name="type" select="1"/>
+                    <field name="hours"/>
+                </tree>
+                ]]>
+            </field>
+        </record>
+        <record model="ir.action.act_window" id="act_work_type_tree2">
+            <field name="name">Work Types</field>
+            <field name="res_model">timesheet.work_type</field>
+            <field name="view_type">tree</field>
+            <field name="domain">[('parent', '=', False)]</field>
+        </record>
+        <record model="ir.action.act_window.view"
+            id="act_work_type_tree_view2">
+            <field name="sequence" eval="10"/>
+            <field name="view" ref="work_type_view_tree3"/>
+            <field name="act_window" ref="act_work_type_tree2"/>
+        </record>
+        <record model="ir.action.wizard" id="act_open_work_type">
+            <field name="name">Open Work Types</field>
+            <field name="wiz_name">timesheet.work_type.open</field>
+        </record>
+        <menuitem parent="menu_timesheet" action="act_open_work_type"
+            id="menu_work_type_tree2" icon="STOCK_INDENT" sequence="40"/>
+
         <record model="ir.model.access" id="access_work_type">
             <field name="model" search="[('model', '=', 'timesheet.work_type')]"/>
             <field name="perm_read" eval="True"/>