Can't seem to figure out RequestScoped...

[DtrollMC]

I've been reading a few books lately, one of them being Java EE 7 Development with NetBeans 8 (Heffelfinger), and I keep having problems with making the named beans. They seem to work sporadically, sometimes the bean works, other times (most times) I am greeted with this lovely error:

/index.xhtml @8,56 contracts="#{themeSelector.themeName}" WELD-001303: No active contexts for scope type javax.enterprise.context.RequestScoped

When I restart Glassfish, and re-run the application, it will work again. Why is this? Is there any simple way to prevent this? This is generally the bean I am trying to implement:

package com.carvethsolutions.beans;

import java.io.Serializable;
import javax.enterprise.context.RequestScoped;
import javax.inject.Named;

/**
 * A simple Named Bean to select a theme on the webpage
 * @author John L. Carveth
 */
@Named
@RequestScoped
public class ThemeSelector implements Serializable {
    private String themeName = "dark";

    public String getThemeName() {
        return themeName;
    }

    public void setThemeName(String themeName) {
        this.themeName = themeName;
    }
}

and I access the named bean in the xhtml pages using:

#{themeSelector.themeName}

 

Anyone familiar with Java EE, JSF, to help with this?