Bug 156642 [Regression]Script of onPrepare is no effect
Details: Script of onPrepare is no effect Set any function on onPrepare, but it is no effect. For example: this.getStyle().color="red" Excepted: it is effect
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/RunTask.java
{
		setRunningFlag( true );
		ReportRunnable report = executionContext.getRunnable( );
		
		if ( !validateParameters( ) )
		{
			setRunningFlag( false );
			throw new EngineException(
					MessageConstants.INVALID_PARAMETER_EXCEPTION ); 
		}
		loadDesign( );
		prepareDesign( );
		startFactory( );
		openReportDocument( );
		try
		{
			writer.saveDesign( report );
			writer.saveParamters( inputValues );
			executionContext.openDataEngine( );
			synchronized(this)
			{
				if (!executionContext.isCanceled( ))
				{
					documentBuilder = new ReportDocumentBuilder(
							executionContext, writer );
				}
			}
			
			if ( documentBuilder != null )
			{