Bug 182000 Cross tab layout behavior
In the current approach of cross tab layout view, the arrow is associated with the first data item in the cell. - User cannot delete measure and level data items which have arrow with them. -Wenbin has concerns with the approach, as this will make the UI very restrictive. - Also user may want to delete data item and just show image in a cross tab cell. We had a discussion with Bang, and he has revised the mockups for the layout - The idea is that the arrow is associated with the cross tab cell and not data item. Let us know if there are any issues with supporting this.
xtab/org.eclipse.birt.report.item.crosstab.ui/src/org/eclipse/birt/report/item/crosstab/internal/ui/editors/model/CrosstabHandleAdapter.java
* 
	 * @param list
	 * @param adapter
	 */
	private void addToModel( List list, BaseCrosstabAdapter adapter )
	{
		if ( list.contains( adapter ) )
		{
			return;
		}
		else if ( oldModelList.contains( adapter ) )
		{
			int index = oldModelList.indexOf( adapter );
			BaseCrosstabAdapter copy = (BaseCrosstabAdapter) oldModelList
					.get( index );
			list.add( adapter.copyToTarget( copy ) );
		}
		else
		{
			list.add( adapter );
		}
	}
	private CrosstabReportItemHandle getCrosstabReportItemHandle( )
	{
		return (CrosstabReportItemHandle) getCrosstabItemHandle( );
	}
	/**
	 * DefaultCrocsstabCellAdapterFactory
	 */
	protected class DefaultCrocsstabCellAdapterFactory