Bug 210609 [Smoke]Crosstab is failed to preview in runtime
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/extension/ExtensionPointManager.java
/**
	 * Returns the provider factory for the given element.
	 * 
	 * @param elementName
	 *            the name of the element
	 * @return the provider factory, or null if there's no factory defined for
	 *         the element
	 */
	public IProviderFactory getProviderFactory( String elementName )
	{
		return (IProviderFactory) getProviderFactoryMap( ).get( elementName );
	}
	private Map getReportItemUIMap( )
	{
		synchronized ( this )
		{
			if ( reportItemUIMap == null )
			{
				reportItemUIMap = new HashMap( );
				for ( Iterator iter = getExtensionElements( IExtensionConstants.EXTENSION_REPORT_ITEM_UI ).iterator( ); iter.hasNext( ); )
				{
					IExtension extension = (IExtension) iter.next( );
					ExtendedElementUIPoint point = createReportItemUIPoint( extension );
					if ( point != null )
						reportItemUIMap.put( point.getExtensionName( ), point );
				}
			}
		}
		return reportItemUIMap;
	}