Redirect in portlet does not work because of Render Parameter

At the end of the portlet action phase the MyFacesGenericPortlet sets a render parameter.

response.setRenderParameter(VIEW_ID, facesContext.getViewRoot().getViewId());

This is not allowed if redirect has already been called on the external context during the action phase of the jsf lifecycle. I believe for redirect case a flag should be used to indicate the the render parameter should not be set.