Bug 142432 MasterPage from library can't be restored to modify
Details: MasterPage from library can't be restored to modify Step: 1.New a library named lib1, and insert a masterpage named lib-mp. 2.Publish the library into resource folder. 3.New a report design and use lib1. 4.Drop the lib-mp from library explorer into outline of report design. 5.Double click lib-mp, and switch to Property editro tab. 6.Click restore. Actual result: Pop up an error message and said that the master page cannot specify size the page type is not custom.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/DesignElementHandle.java
}
	/**
	 * Returns a array of valid choices for a property.
	 * 
	 * @param propName
	 *            the property name
	 * @return a array containing choices for the given property. Return
	 *         <code>null</code>, if this property has no choice.
	 */
	public IChoice[] getChoices( String propName )
	{
		PropertyHandle propertyHandle = getPropertyHandle( propName );
		if ( propertyHandle == null )
			return null;
		return propertyHandle.getChoices( );
	}
	/**
	 * Returns the short display label for this element.
	 * 
	 * @return the display label of this element in SHORT_LABEL level.
	 * @see #getDisplayLabel( int )
	 */
	public String getDisplayLabel( )
	{
		return getDisplayLabel( DesignElement.SHORT_LABEL );
	}
	/**
	 * Returns the display label for this element. The display label is the
	 * localized display name to be shown in the UI. The display label is one of
	 * the following: