Bug 136270 Group's data binding column can only be used by the group itself
If you add some data binding columns to a group, these columns can only be used by this group itself. It should has a way to make the child can use the parent group's data binding column.
UI/org.eclipse.birt.report.designer.core/src/org/eclipse/birt/report/designer/util/DEUtil.java
{
			px = DimensionUtil.convertTo( measure * fontSize / 100,
					DesignChoiceConstants.UNITS_PT,
					DesignChoiceConstants.UNITS_IN ).getMeasure( );
		}
		
		else if ( "".equals( units ) ) 
		{
			units = SessionHandleAdapter.getInstance( )
					.getReportDesignHandle( )
					.getDefaultUnits( );
			px = DimensionUtil.convertTo( measure,
					units,
					DesignChoiceConstants.UNITS_IN ).getMeasure( );
		}
		else if ( units == null )
		{
			px = 0.0;
		}
		else
		{
			px = DimensionUtil.convertTo( measure,
					units,
					DesignChoiceConstants.UNITS_IN ).getMeasure( );
		}
		return MetricUtility.inchToPixel( px );
	}
	/**
	 * Transform other units to target unit.
	 *