diff --git a/src/adapters/geometryadapter.h b/src/adapters/geometryadapter.h
index 2375397..f999174 100644
--- a/src/adapters/geometryadapter.h
+++ b/src/adapters/geometryadapter.h
@@ -1,164 +1,183 @@
 /***************************************************************************
  *   Copyright (C) 2018 by Emmanuel Lepage Vallee                          *
  *   Author : Emmanuel Lepage Vallee <emmanuel.lepage@kde.org>             *
  *                                                                         *
  *   This program is free software; you can redistribute it and/or modify  *
  *   it under the terms of the GNU General Public License as published by  *
  *   the Free Software Foundation; either version 3 of the License, or     *
  *   (at your option) any later version.                                   *
  *                                                                         *
  *   This program is distributed in the hope that it will be useful,       *
  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  *   GNU General Public License for more details.                          *
  *                                                                         *
  *   You should have received a copy of the GNU General Public License     *
  *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
  **************************************************************************/
 #ifndef KQUICKITEMVIEWS_GEOMETRYADAPTER_H
 #define KQUICKITEMVIEWS_GEOMETRYADAPTER_H
 
 #include <QtCore/QObject>
 #include <QtCore/QSizeF>
 #include <QtCore/QPointF>
 
 class GeometryAdapterPrivate;
 class AbstractItemAdapter;
 class Viewport;
 
 /**
  * Add strategies to get the size (and optionally position) hints.
  *
  * One size don't fit everything here. QtWidgets had a `sizeHint` method.
  * However getting this information in QML is a lot harder for many reasons.
  */
 class Q_DECL_EXPORT GeometryAdapter : public QObject
 {
     Q_OBJECT
 public:
     Q_INVOKABLE explicit GeometryAdapter(Viewport *parent = nullptr);
     virtual ~GeometryAdapter();
 
     /**
      * Features this adapter provide and requires.
      */
     enum Capabilities {
         NONE                      = 0x0 << 0,
 
        /**
         * Most GeometryAdapter only provide size hints.
         *
         * However some views might not have built-in layouts and then the position
         * is also necessary.
         *
         * This property only state that the adapter *can* provide positions.
         * `alwaysHasPositionHints` will tell if this is always the case.
         */
         HAS_POSITION_HINTS        = 0x1 << 0,
 
        /**
         * Allow the view to skip the GeometryAdapter when they only need the height.
         *
         * It will be called once, then the view will assume the result will always
         * be the same.
         */
         HAS_UNIFORM_HEIGHT        = 0x1 << 1,
 
        /**
         * Allow the view to skip the GeometryAdapter when they only need the width.
         *
         * It will be called once, then the view will assume the result will always
         * be the same.
         */
         HAS_UNIFORM_WIDTH         = 0x1 << 2,
 
        /**
         * The sizeHint will *always* return a valid size.
         *
         * Some GeometryAdapter may only provide size hints when some preconditions
         * are met. For example something that depends on the current delegate
         * will only work once the delegate is created.
         */
         ALWAYS_HAS_SIZE_HINTS     = 0x1 << 3,
 
         /** @see alwaysHasSizeHints */
         ALWAYS_HAS_POSITION_HINTS = 0x1 << 4,
 
        /**
         * This GeometryAdapter allows to query the size before creating a
         * delegate instance.
         */
         HAS_AHEAD_OF_TIME         = 0x1 << 5,
 
        /**
         * This GeometryAdapter requires the view to track each QQuickItem
         * delegate geometry.
         */
         TRACKS_QQUICKITEM_GEOMETRY= 0x1 << 6,
 
        /**
         * This GeometryAdapter requires a single delegate instance to work.
         */
         REQUIRES_SINGLE_INSTANCE  = 0x1 << 7,
 
        /**
         * Apply the size hints instead of using the delegate implicit size.
         */
         FORCE_DELEGATE_SIZE       = 0x1 << 8,
+
+        /**
+         * Each QModelIndex, including the children QModelIndex or positioned
+         * one after the other in a Cartesian plane. This capability is only
+         * relevant when HAS_POSITION_HINTS is set and implies
+         * HAS_ORDERED_SIBLINGS.
+         *
+         * Do not set this hint if the
+         */
+        IS_ORDERED                = 0x1 << 9,
+
+        /**
+         * When the QModelIndex with the same parent are positioned next to
+         * each other on a Cartesian plane.
+         *
+         * Use IS_ORDERED if this is also true among QModelIndex of different
+         * parent.
+         */
+        HAS_ORDERED_SIBLINGS      = 0x1 << 10,
     };
 //     Q_FLAGS(Capabilities)
 
     /**
      * A feature set provided by this adapter.
      */
     Q_PROPERTY(int capabilities READ capabilities NOTIFY flagsChanged)
 
     /**
      * If the GeometryAdapter should override the delegate implicit size
      * with the size hints.
      */
     Q_PROPERTY(bool forceSize READ isSizeForced WRITE setSizeForced NOTIFY flagsChanged)
 
     virtual int capabilities() const;
 
     virtual bool isSizeForced() const;
     virtual void setSizeForced(bool f);
 
     /**
      * Get the size hints for an AbstractItemAdapter.
      */
     Q_INVOKABLE virtual QSizeF sizeHint(const QModelIndex &index, AbstractItemAdapter *adapter) const;
 
     /**
      * Get the position hints for an AbstractItemAdapter.
      */
     Q_INVOKABLE virtual QPointF positionHint(const QModelIndex &index, AbstractItemAdapter *adapter) const;
 
     Viewport *viewport() const;
 
 protected:
     /**
      * Set the flags to be used by the internal optimization engine.
      */
     void setCapabilities(int f);
 
     void addCapabilities(int f);
 
     void removeCapabilities(int f);
 
 Q_SIGNALS:
 
     /**
      * Tell the view to disregard previously returned values and start over.
      */
     void dismissResult();
 
     void flagsChanged();
 
 
 private:
     GeometryAdapterPrivate *d_ptr;
     Q_DECLARE_PRIVATE(GeometryAdapter)
 };
 
 #endif