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
*/
	public UserPropertyDefnHandle getUserPropertyDefnHandle( String propName )
	{
		DesignElement element = getElement( );
		ElementPropertyDefn propDefn = element.getPropertyDefn( propName );
		if ( propDefn == null )
			return null;
		if ( propDefn.isUserProperty( ) )
		{
			return new UserPropertyDefnHandle( this,
					(UserPropertyDefn) propDefn );
		}
		return null;
	}
	/**
	 * Returns a list of user properties defined in this element and somewhere
	 * up the inheritance chain. Each object in the list is instance of
	 * <code>UserPropertyDefn</code>.
	 * 
	 * @return The list of user property definitions
	 */
	public List getUserProperties( )
	{
		return getElement( ).getUserProperties( );
	}
	/**
	 * Returns a handle for a top-level property for use in preparing the
	 * Factory data structures. This handle follows specialized rules:
	 * <p>
	 * <ul>