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/SimpleGroupElementHandle.java
* @see org.eclipse.birt.report.model.api.GroupElementHandle#isSameType()
	 */
	public boolean isSameType( )
	{
		if ( elements.size( ) == 0 )
			return false;
		IElementDefn baseDefn = null;
		for ( int i = 0; i < elements.size( ); i++ )
		{
			Object item = elements.get( i );
			if ( !( item instanceof DesignElementHandle ) )
				return false;
			IElementDefn elemDefn = ( (DesignElementHandle) item ).getDefn( );
			if ( baseDefn == null )
				baseDefn = elemDefn;
			if ( elemDefn != baseDefn )
				return false;
		}
		return true;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.model.api.GroupElementHandle#visiblePropertyIterator()
	 */
	public Iterator visiblePropertyIterator( )
	{
		List list = getCommonProperties( );
		final List visibleList = new ArrayList( );
		for ( int i = 0; i < list.size( ); i++ )