public void CommandImportMerge(object param)
        {
            if (!TilePoolExists(param))
            {
                return;
            }

            Guid     uid      = (Guid)param;
            TilePool tilePool = Editor.Project.TilePoolManager.Pools[uid];

            using (ImportTilePool form = new ImportTilePool(tilePool.Name, tilePool.TileWidth, tilePool.TileHeight)) {
                if (form.ShowDialog() == DialogResult.OK && form.Pool != null)
                {
                    tilePool.Merge(form.Pool, TileImportPolicy.SetUnique);
                }
            }
        }