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 instance.
	 */
	private static Logger logger = Logger
			.getLogger( DimensionPropertyType.class.getName( ) );
	/**
	 * Display name key.
	 */
	private static final String DISPLAY_NAME_KEY = "Property.dimension"; 
	/**
	 * Constructor.
	 */
	public DimensionPropertyType( )
	{
		super( DISPLAY_NAME_KEY );
	}
	/**
	 * Validates the dimension property value, the value can be one of the
	 * followings:
	 * <ul>
	 * <li>Null, meaning to clear the property value.</li>
	 * <li>A string with optional units. The string is of the form n( *)[u]
	 * where n is a decimal number with the decimal separator specified by the
	 * current locale, ( *) is optional white space, and [u] is an optional
	 * units specifier. Units can be any of the recognized BIRT units: in, cm,
	 * mm, pt, pc, px, em, ex or % . If the unit specifier is omitted, use the
	 * default for the design.</li>