Bug 211991 Page header items when in a grid within a grid disappear on runtime render
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/layout/html/HTMLPageLM.java
if(header!=null)
		{
			pageContent.setPageHeader( layoutContent(header) );
		}
		IContent footer = pageContent.getPageFooter( );
		if(footer!=null)
		{
			pageContent.setPageFooter( layoutContent(footer) );
		}
		
	}
	
	protected IContent layoutContent(IContent content)
	{
		if(content==null)
		{
			return null;
		}
		ContentDOMEmitter domEmitter = new ContentDOMEmitter(content, emitter);		
		boolean pageBreak = context.allowPageBreak( );
		IPageBuffer pageBuffer = context.getPageBufferManager( );
		context.setPageBufferManager( new PageContentBuffer() );
		context.setAllowPageBreak( false );
		engine.layout(this, content, domEmitter );
		context.setAllowPageBreak( pageBreak );
		context.setPageBufferManager( pageBuffer );
		domEmitter.refreshChildren( );
		return content;
	}