Bug 163018 An error extension will lead the report contain chart can't be opened and can not new a report.
Details: An error extension will lead the report contain chart can't open In org.eclipse.birt.report.tests.model has an error extension. When run the birt use workbenck, the report contain chart can't be opened and it can not new a report.
model/org.eclipse.birt.report.model.tests/test/org/eclipse/birt/report/model/extension/PeerExtensionTest.java
{
		openDesign( FILE_NAME );
		ExtendedItemHandle extendedItem = (ExtendedItemHandle) designHandle
				.findElement( "testBox" ); 
		assertNotNull( extendedItem );
		
		SlotHandle slot = extendedItem.getSlot( 1 );
		LabelHandle label = designHandle.getElementFactory( ).newLabel(
				"addLabel" ); 
		slot.add( label );
		IDesignElement clonedExtendedItem = extendedItem.copy( );
		designHandle.rename( clonedExtendedItem.getHandle( design ) );
		slot.paste( clonedExtendedItem );
		
		ExtendedItemHandle extendedTable = designHandle.getElementFactory( )
				.newExtendedItem( "testExtendedTable", "TestingTable" ); 
		extendedTable.setProperty( TableItem.CAPTION_PROP, "table caption" ); 
		extendedTable.setProperty( TableItem.DATA_SET_PROP, "tableDataSet" ); 
		extendedTable.setProperty( IStyleModel.COLOR_PROP, IColorConstants.RED );
		extendedTable.setProperty( "usage", "testusagevalue" ); 
		designHandle.getBody( ).add( extendedTable );
		save( );
		assertTrue( compareFile( "PeerExtensionTest_golden.xml" ) ); 
	}
	/**
	 * Tests the property search with support of extension slot.
	 * 
	 * @throws Exception
	 */
	public void testPropertySearch( ) throws Exception