source: branches/WebJobManager/HeuristicLab.ExtLibs/HeuristicLab.WinFormsUI/2.7.0/WinFormsUI-2.7.0/Docking/DockPaneCollection.cs

using System;
using System.Collections.ObjectModel;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;

namespace WeifenLuo.WinFormsUI.Docking
{
  public class DockPaneCollection : ReadOnlyCollection<DockPane>
  {
        internal DockPaneCollection()
            : base(new List<DockPane>())
        {
        }

    internal int Add(DockPane pane)
    {
      if (Items.Contains(pane))
        return Items.IndexOf(pane);

      Items.Add(pane);
            return Count - 1;
    }

    internal void AddAt(DockPane pane, int index)
    {
      if (index < 0 || index > Items.Count - 1)
        return;
      
      if (Contains(pane))
        return;

      Items.Insert(index, pane);
    }

    internal void Dispose()
    {
      for (int i=Count - 1; i>=0; i--)
        this[i].Close();
    }

    internal void Remove(DockPane pane)
    {
      Items.Remove(pane);
    }
  }
}