diff --git a/kfet/static/kfet/js/history.js b/kfet/static/kfet/js/history.js
index a41173b2..9578b83d 100644
--- a/kfet/static/kfet/js/history.js
+++ b/kfet/static/kfet/js/history.js
@@ -19,10 +19,10 @@ class KHistory {
         
         this.list = new OperationList();
 
-        if (!options.no_select)
+        if (!options || !options.no_select)
             this.selection = new KHistorySelection(this);
 
-        if (options.no_trigramme) 
+        if (options && options.no_trigramme) 
             this.templates['opegroup'] = '<div class="opegroup"><span class="time"></span><span class="amount"></span><span class="valid_by"></span><span class="comment"></span></div>'
  
         this._init_events();
@@ -80,7 +80,7 @@ class KHistory {
 
     add_node(data) {
         var node = this.list.get_or_create(data, 0);
-        this.list.add_to_container(this._$container, node, this.templates, this.display_options);
+        this.list.add_to_container(this._$container, node, this.templates);
     }
 
     update_node(type, id, update_data) {
@@ -88,8 +88,8 @@ class KHistory {
         if (!to_update) 
             return false;
 
-        $.extend(to_update.content, update_data);
-        var $new_elt = to_update.content.display($(this.templates[type]), this.display_options);
+        $.extend(to_update, update_data);
+        var $new_elt = to_update.display($(this.templates[type]), {});
 
         var $to_replace = this._$container.find('#'+type+'-'+id+'>:first-child');
         $to_replace.replaceWith($new_elt);
@@ -100,22 +100,22 @@ class KHistory {
     is_valid(opegroup) {
         var options = this.api_options;
 
-        if (options.from && dateUTCToParis(opegroup.content.at).isBefore(moment(options.from)))
+        if (options.from && dateUTCToParis(opegroup.at).isBefore(moment(options.from)))
             return false;
 
-        if (options.to && dateUTCToParis(opegroup.content.at).isAfter(moment(options.to)))
+        if (options.to && dateUTCToParis(opegroup.at).isAfter(moment(options.to)))
             return false;
 
-        if (options.transfersonly && opegroup.modelname === 'opegroup')
+        if (options.transfersonly && opegroup.constructor.verbose_name === 'opegroup')
             return false;
 
         if (options.accounts && options.accounts.length &&
-                options.accounts.indexOf(opegroup.content.account_id) < 0)
+                options.accounts.indexOf(opegroup.account_id) < 0)
             return false;
 
         if (options.checkouts && options.checkouts.length && 
                 (opegroup.modelname === 'transfergroup' || 
-                 options.checkouts.indexOf(opegroup.content.checkout_id) < 0))
+                 options.checkouts.indexOf(opegroup.checkout_id) < 0))
             return false;
             
         return true;
diff --git a/kfet/static/kfet/js/kfet.api.js b/kfet/static/kfet/js/kfet.api.js
index e08efced..6afc179f 100644
--- a/kfet/static/kfet/js/kfet.api.js
+++ b/kfet/static/kfet/js/kfet.api.js
@@ -565,14 +565,20 @@ class Day extends ModelObject {
      * @default <tt>['id', 'date']</tt>
      * @see {@link Models.ModelObject.props|ModelObject.props}
      */
-    static get props() { return ['id', 'date'] }
+    static get props() { return ['id', 'date', 'opegroups'] }
 
     /**
      * Default values for Day model instances
      * @default <tt>{'id': '', 'date': moment()}</tt>
      * @see {@link Models.ModelObject.default_data|ModelObject.default_data}
      */
-    static get default_data() { return {'id': '', 'date': moment()}; }
+    static get default_data() { return {'id': '', 'date': moment(), 'opegroups': []}; }
+
+    /**
+     * Verbose name for Article model
+     * @default <tt>'day'</tt>
+     */
+    static get verbose_name() { return 'day'; }
 
     /**
      * @default {@link Formatters.DayFormatter}
@@ -610,7 +616,7 @@ class HistoryGroup extends ModelObject {
      * @see {@link Models.ModelObject.props|ModelObject.props}
      */
     static get props() {
-        return ['id', 'at', 'comment', 'valid_by'];
+        return ['id', 'at', 'comment', 'valid_by', 'day'];
     }
 
     /**
@@ -621,7 +627,7 @@ class HistoryGroup extends ModelObject {
      */
     static get default_data() {
         return {'id': 0, 'at': moment(), 'comment': '', 
-            'valid_by': '',};
+            'valid_by': '', 'day': new Day()};
     }
 
     /**
@@ -665,9 +671,17 @@ class OperationGroup extends HistoryGroup {
      */
     static get default_data() {
         return $.extend({}, HistoryGroup.default_data, 
-                            {'amount': 0, 'is_cof': false, 'trigramme': ''});
+                            {'amount': 0, 'is_cof': false, 'trigramme': '', 
+                             'opes': []});
     }
 
+    /**
+     * Verbose name for OperationGroup model
+     * @default <tt>'opegroup'</tt>
+     */
+    static get verbose_name() { return 'opegroup'; }
+
+
     /**
      * @default {@link Formatters.OpegroupFormatter}
      */
@@ -686,6 +700,24 @@ class OperationGroup extends HistoryGroup {
  */
 class TransferGroup extends HistoryGroup {
     
+    /**
+     * Default values for OperationGroup instances.
+     * @default <tt>{@link Models.HistoryGroup.default_data|HistoryGroup.default_data} + 
+     * {'transfers': []}</tt>
+     * @see {@link Models.ModelObject.default_data|ModelObject.default_data}
+     */
+    static get default_data() {
+        return $.extend({}, HistoryGroup.default_data, 
+                            {'transfers': []});
+    }
+
+    /**
+     * Verbose name for TransferGroup model
+     * @default <tt>'transfergroup'</tt>
+     */
+    static get verbose_name() { return 'transfergroup'; }
+
+
     /**
      * @default {@link Formatters.TransferGroupFormatter}
      */
@@ -707,7 +739,7 @@ class Operation extends ModelObject {
      * @see {@link Models.ModelObject.props|ModelObject.props}
      */
     static get props() {
-        return ['id', 'amount', 'canceled_at', 'canceled_by'];
+        return ['id', 'amount', 'canceled_at', 'canceled_by', 'group'];
     }
 
     /**
@@ -716,7 +748,8 @@ class Operation extends ModelObject {
      * @see {@link Models.ModelObject.default_data|ModelObject.default_data}
      */
     static get default_data() {
-        return {'id': '', 'amount': 0, 'canceled_at': undefined, 'canceled_by': '' };
+        return {'id': '', 'amount': 0, 'canceled_at': undefined, 'canceled_by': '',
+                'group': new HistoryGroup()};
     }
 
     get amount()  { return this._amount; }
@@ -765,6 +798,13 @@ class Purchase extends Operation {
         });
     }
 
+    /**
+     * Verbose name for Purchase model
+     * @default <tt>'purchase'</tt>
+     */
+    static get verbose_name() { return 'purchase'; }
+
+
     /**
      * @default {@link Formatters.PurchaseFormatter}
      */
@@ -786,9 +826,16 @@ class SpecialOperation extends Operation {
      * @see {@link Models.ModelObject.props|ModelObject.props}
      */
     static get props() {
-        return Operation.props.concat(['type', 'is_checkout']);
+        return Operation.props.concat(['type']);
     }
 
+    /**
+     * Verbose name for SpecialOperation model
+     * @default <tt>'specialope'</tt>
+     */
+    static get verbose_name() { return 'specialope'; }
+
+
     /**
      * Verbose names for operation types
      * @type {Object}
@@ -808,7 +855,7 @@ class SpecialOperation extends Operation {
      * @see {@link Models.ModelObject.default_data|ModelObject.default_data}
      */
     static get default_data() {
-        return $.extend({}, Operation.default_data, {'type': '', 'is_checkout': false});
+        return $.extend({}, Operation.default_data, {'type': ''});
     }
 
     /**
@@ -835,6 +882,12 @@ class Transfer extends Operation {
         return Operation.props.concat(['from_acc', 'to_acc']);
     }
 
+    /**
+     * Verbose name for Transfer model
+     * @default <tt>'transfer'</tt>
+     */
+    static get verbose_name() { return 'transfer'; }
+
     /**
      * Default values for Transfer model instances
      * @default <tt>{@link Models.Operation.default_data|Operation.default_data} + {'from_acc': '', 'to_acc': ''}
@@ -873,6 +926,13 @@ class ModelForest {
         this.from(datalist || []);
     }
 
+    /**
+     * Return true if instance is empty
+     */
+    is_empty() {
+        return this.roots.length == 0;
+    }
+
     /**
      * Shortcut functions to get parent and children of a given node
      */
@@ -920,11 +980,11 @@ class ModelForest {
 
         if (direction >= 0) {
             var child_name = struct_data.children;
-            var child_struct = this.constructor.structure[child_name];
             if (data.children && data.children.length) {
                 for (let child_data of data.children) {
                     var child = this.get_or_create(child_data, 1);
-                    child[child_struct.parent] = node;
+                    var child_parent = this.constructor.structure[child.constructor.verbose_name];
+                    child[child_parent] = node;
                     node[child_name].push(child);
                 }
             }
@@ -1008,7 +1068,8 @@ class ModelForest {
 
         var $to_insert = this.render_element(first_missing, templates, options);
         if (existing) {
-            $container.find('#'+existing.modelname+'-'+existing.content.id+'>:first-child').after($to_insert);
+            $container.find('#'+existing.constructor.verbose_name+'-'+existing.id+'>:first-child')
+                      .after($to_insert);
         } else {
             $container.prepend($to_insert);
         }
@@ -1021,6 +1082,9 @@ class ModelForest {
      * @param {Object} [options] Options for element render method
      */
     display($container, templates, options) {
+        if (this.is_empty())
+            return;
+
         if (this.constructor.root_sort)
             this.roots.sort(this.constructor.root_sort);
         else
@@ -1161,14 +1225,34 @@ class OperationList extends APIModelForest {
      * @default <tt>[Operation, OperationGroup, Day]</tt>
      * @see {@link Models.ModelList.models|ModelList.models}
      */
-    static get models() {
+    static get structure() {
         return {
-            'day': Day,
-            'opegroup': OperationGroup,
-            'transfergroup': TransferGroup,
-            'purchase': Purchase,
-            'specialope': SpecialOperation,
-            'transfer': Transfer,
+            'day': {
+                'model': Day,
+                'children': 'opegroups'
+            },
+            'opegroup': {
+                'model': OperationGroup,
+                'parent': 'day',
+                'children': 'opes',
+            },
+            'transfergroup': {
+                'model': TransferGroup,
+                'parent': 'day', 
+                'children': 'transfers'
+            },
+            'purchase': {
+                'model': Purchase,
+                'parent': 'opegroup',
+            },
+            'specialope': {
+                'model': SpecialOperation,
+                'parent': 'opegroup',
+            },
+            'transfer': {
+                'model': Transfer,
+                'parent': 'transfergroup',
+            },
         };
     }
 
@@ -1583,10 +1667,10 @@ class OperationFormatter extends Formatter {
 
     /**
      * Properties renderable to html.
-     * @default <tt>['amount', 'infos1', 'infos2', 'addcost', 'canceled']</tt>
+     * @default <tt>['amount', 'infos1', 'infos2', 'canceled']</tt>
      */
     static get props() {
-        return ['amount', 'infos1', 'infos2', 'addcost', 'canceled'];
+        return ['amount', 'infos1', 'infos2', 'canceled'];
     }
 
     static get attrs() {
@@ -1597,19 +1681,7 @@ class OperationFormatter extends Formatter {
      * <tt>a.amount</tt> displayed according to <tt>a.is_cof</tt> and <tt>a.trigramme</tt> values.
      */
     static prop_amount(a) {
-        return amountDisplay(a.amount, a.is_cof, a.trigramme);
-    }
-
-    /**
-     * <tt>addcost</tt> property is displayed iff <tt>a.addcost_for</tt> is nonempty.
-     */
-    static prop_addcost(a) {
-        if (a.addcost_for) {
-            return '('+amountDisplay(a.addcost_amount, a.is_cof)
-                    +'UKF pour '+a.addcost_for+')';
-        } else {
-            return '';
-        }
+        return amountDisplay(a.amount, a.group.is_cof, a.group.trigramme);
     }
 
     /**
@@ -1639,6 +1711,22 @@ class OperationFormatter extends Formatter {
  */
 class PurchaseFormatter extends OperationFormatter {
 
+    static get props() {
+        return OperationFormatter.props.concat(['addcost']);
+    }
+
+    /**
+     * <tt>addcost</tt> property is displayed iff <tt>a.addcost_for</tt> is nonempty.
+     */
+    static prop_addcost(a) {
+        if (a.addcost_for) {
+            return '('+amountDisplay(a.addcost_amount, a.is_cof)
+                    +'UKF pour '+a.addcost_for+')';
+        } else {
+            return '';
+        }
+    }
+
     static prop_infos1(a) {
         return a.article_nb;
     }
diff --git a/kfet/templates/kfet/kpsul.html b/kfet/templates/kfet/kpsul.html
index 3aefb527..c1e5fec6 100644
--- a/kfet/templates/kfet/kpsul.html
+++ b/kfet/templates/kfet/kpsul.html
@@ -648,72 +648,6 @@ $(document).ready(function() {
     }
 
 
-<<<<<<< HEAD
-=======
-    // -----
-    // Cancel from history
-    // -----
-
-    khistory.$container.selectable({
-        filter: 'div.opegroup, div.ope',
-        selected: function(e, ui) {
-            $(ui.selected).each(function() {
-                if ($(this).hasClass('opegroup')) {
-                    var opegroup = $(this).data('opegroup');
-                    $(this).siblings('.ope').filter(function() {
-                        return $(this).data('opegroup') == opegroup
-                    }).addClass('ui-selected');
-                }
-            });
-        },
-    });
-
-    $(document).on('keydown', function (e) {
-        if (e.keyCode == 46) {
-            // DEL (Suppr)
-            var opes_to_cancel = [];
-            khistory.$container.find('.ope.ui-selected').each(function () {
-                opes_to_cancel.push($(this).data('ope'));
-            });
-            if (opes_to_cancel.length > 0)
-                cancelOperations(opes_to_cancel);
-        }
-    });
-
-    // -----
-    // Synchronization
-    // -----
-
-    OperationWebSocket.add_handler(function(data) {
-        for (var i=0; i<data['opegroups'].length; i++) {
-            if (data['opegroups'][i]['add']) {
-                khistory.addOpeGroup(data['opegroups'][i]);
-            } else if (data['opegroups'][i]['cancellation']) {
-                khistory.cancelOpeGroup(data['opegroups'][i]);
-            }
-        }
-        for (var i=0; i<data['opes'].length; i++) {
-            if (data['opes'][i]['cancellation']) {
-                khistory.cancelOpe(data['opes'][i]);
-            }
-        }
-        for (var i=0; i<data['checkouts'].length; i++) {
-            if (checkout_data['id'] == data['checkouts'][i]['id']) {
-                checkout_data['balance'] = data['checkouts'][i]['balance'];
-                displayCheckoutData();
-            }
-        }
-
-        kpsul.article_manager.update_data(data);
-
-        if (data['addcost']) {
-            Config.set('addcost_for', data['addcost']['for']);
-            Config.set('addcost_amount', data['addcost']['amount']);
-            displayAddcost();
-        }
-    });
->>>>>>> origin/aureplop/kpsul_js_refactor
-
     // -----
     // General
     // -----
diff --git a/kfet/views.py b/kfet/views.py
index 57e7ae95..7826f31d 100644
--- a/kfet/views.py
+++ b/kfet/views.py
@@ -1168,7 +1168,6 @@ def kpsul_perform_operations(request):
     websocket_data = {}
     websocket_data['opegroups'] = [{
         'add': True,
-<<<<<<< HEAD
         'modelname': 'opegroup',
         'content': {
             'id': operationgroup.pk,
@@ -1189,48 +1188,17 @@ def kpsul_perform_operations(request):
                 'id': operationgroup.at.strftime('%Y%m%d'),
                 'date': operationgroup.at
             },
-            'child_sort': 'opegroup',
         },
         'children': [],
-=======
-        'id': operationgroup.pk,
-        'amount': operationgroup.amount,
-        'checkout__name': operationgroup.checkout.name,
-        'at': operationgroup.at,
-        'is_cof': operationgroup.is_cof,
-        'comment': operationgroup.comment,
-        'valid_by__trigramme': (operationgroup.valid_by and
-                                operationgroup.valid_by.trigramme or None),
-        'on_acc__trigramme': operationgroup.on_acc.trigramme,
-        'opes': [],
->>>>>>> origin/aureplop/kpsul_js_refactor
     }]
     for ope in operations:
         ope_data = {
-<<<<<<< HEAD
             'content': {
                 'id': ope.id,
                 'amount': ope.amount,
-                'canceled_at': ope.canceled_at,
-                'canceled_by':
-                    ope.canceled_by and ope.canceled_by.trigramme or None,
-                'is_cof': operationgroup.is_cof,
-                'trigramme': (
-                    operationgroup.on_acc and
-                    operationgroup.on_acc.trigramme or None),
+                'canceled_at': None,
+                'canceled_by': None,
             },
-=======
-            'id': operation.pk, 'type': operation.type,
-            'amount': operation.amount,
-            'addcost_amount': operation.addcost_amount,
-            'addcost_for__trigramme': (
-                operation.addcost_for and addcost_for.trigramme or None),
-            'article__name': (
-                operation.article and operation.article.name or None),
-            'article_nb': operation.article_nb,
-            'group_id': operationgroup.pk,
-            'canceled_by__trigramme': None, 'canceled_at': None,
->>>>>>> origin/aureplop/kpsul_js_refactor
         }
 
         if ope.type == Operation.PURCHASE:
@@ -1246,7 +1214,6 @@ def kpsul_perform_operations(request):
             ope_data['modelname'] = 'specialope'
             ope_data['content'].update({
                 'type': ope.type,
-                'is_checkout': ope.is_checkout,
             })
         websocket_data['opegroups'][0]['children'].append(ope_data)
     # Need refresh from db cause we used update on queryset
@@ -1586,7 +1553,6 @@ def history_json(request):
                     'id': opegroup.at.strftime('%Y%m%d'),
                     'date': opegroup.at
                 },
-                'child_sort': 'opegroup',
             },
             'children': [],
         }
@@ -1643,7 +1609,6 @@ def history_json(request):
                         'id': transfergroup.at.strftime('%Y%m%d'),
                         'date': transfergroup.at
                     },
-                    'child_sort': 'transfergroup',
                 },
                 'children': [],
             }