Open On does not work for files in this tags when EL variable is used to specify file location:

<h:graphicImage value="#

{facesContext.externalContext.requestContextPath}/img/seamlogo.png"/>
<a:loadStyle src="#{facesContext.externalContext.requestContextPath}

/stylesheet/theme.css"/>
<link href="#

{facesContext.externalContext.requestContextPath}

/stylesheet/theme.css"/>

Pages are rendered properly in VPE.