private void GroupSelectedItems()
        {
            var sbl   = BlockList.GetSelectedBlockList();
            int count = sbl.listBlocks.SelectedItems.Count;

            if (count == 0)
            {
                System.Media.SystemSounds.Beep.Play();
                return;
            }

            string prompt;

            if (count == 1)
            {
                prompt = "Group Selected Block?";
            }
            else if (count == sbl.listBlocks.Items.Count)
            {
                prompt = "Group All Blocks?";
            }
            else
            {
                prompt = string.Format("Group {0} Selected Blocks?", sbl.listBlocks.SelectedItems.Count);
            }

            if (MessageBox.Show(prompt, "Block Editor", MessageBoxButton.OKCancel, MessageBoxImage.Question) == MessageBoxResult.OK)
            {
                inSelectionChanged = true;
                IBlockGroup   group     = BlockManager.NewBlockGroup();
                List <IBlock> blockList = new List <IBlock>();
                blockList.AddRange(sbl.Blocks);

                IBlock[] selectedBlocks = sbl.AdjacentSelectedBlocks;
                int      index          = blockList.IndexOf(selectedBlocks[0]);
                blockList.Insert(index, group);
                foreach (IBlock block in selectedBlocks)
                {
                    group.Add(block);
                    blockList.Remove(block);
                }
                foreach (IBlock block in blockList)
                {
                    block.NewBlockItem();
                }
                sbl.Clear();
                sbl.Add(blockList.ToArray());
                sbl.listBlocks.SelectedItem = group.BlockItem;
                listCode.UnselectAll();

                if (sbl.ParentGroup != null)
                {
                    sbl.ParentGroup.Blocks = sbl.Blocks;
                }

                Edited = true;
                btnDelete.IsEnabled = btnCut.IsEnabled = btnCopy.IsEnabled = btnGroup.IsEnabled = btnUngroup.IsEnabled = true;
                inSelectionChanged  = false;
            }
        }