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/editpolicies/CrosstabCellFlowLayoutEditPolicy.java
if (afterObj != parentAdapter.getFirstDataItem( ))
					{
						afterObj = null;
					}
					if (childAdapter.getCrosstabCellHandle( ).getCrosstab( ) == parentAdapter.getCrosstabCellHandle( ).getCrosstab( ))
					{
						return new ChangeMeasureOrderCommand(parentAdapter.getDesignElementHandle( ), 
								childAdapter.getDesignElementHandle( ),(DesignElementHandle) DNDUtil.unwrapToModel( afterObj ) );
					}
					else
					{
						return UnexecutableCommand.INSTANCE;
					}
					
				}
		}
		if (childParent instanceof CrosstabCellAdapter)
		{	
			CrosstabCellAdapter childAdapter = (CrosstabCellAdapter)childParent;
			if (isFirstDataItem( childAdapter, child.getModel( ), ICrosstabCellAdapterFactory.CELL_FIRST_LEVEL_HANDLE )
					|| isFirstDataItem( childAdapter, child.getModel( ), ICrosstabCellAdapterFactory.CELL_MEASURE ))
			{
				return UnexecutableCommand.INSTANCE;
			}
		}
		return new CrosstabPasterCommand( (DesignElementHandle) DNDUtil.unwrapToModel( source ),
				(DesignElementHandle) DNDUtil.unwrapToModel( parentObj ),
				(DesignElementHandle) DNDUtil.unwrapToModel( afterObj ) );
	}