Bug 214212 Problem occurs when set the masterpage margin with ems/exs/pixcel units.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/metadata/DimensionPropertyType.java
{
			logger.log( Level.FINE, "return dimension with user-defined unit " 
					+ dim.toString( ) );
			return dim;
		}
		dim = new DimensionValue( dim.getMeasure( ), getDefaultUnit( module,
				defn ) );
		logger.log( Level.FINE,
				"return dimension with default unit " + dim.toString( ) ); 
		return dim;
	}
	/**
	 * Converts the value into a locale-dependent string. The measure part of
	 * the <code>DimensionValue</code> will be formatted in the current
	 * locale, e.g: 12,000,000.123 for US locale while in German the value it
	 * will be 12.000.000,123. The unit will be attached after the measure.
	 */
	public String toDisplayString( Module module, PropertyDefn defn,
			Object value )
	{
		if ( value == null )
			return null;
		assert value instanceof DimensionValue;
		
		
		return ( (DimensionValue) value ).toDisplayString( );
	}
	/**
	 * Validates the unit of the dimension value, checks to see if it is in the
	 * allowed units set.