title: Why doesn't h:commandButton execute the action method when combined with c:chose?
body: <p>I've seen a strange problem in my project. It's that <code>&lt;h:commandButton/&gt;</code> does not execute the action method.</p>
  
  <pre><code>&lt;c:choose&gt;
     &lt;c:when test="#{empty param.t}"&gt;
         // HTML
     &lt;/c:when&gt;
     &lt;c:when test="#{param.t eq 'normal'}"&gt;
         // HTML
         &lt;h:form&gt;
             &lt;h:commandButton value="ADD" action="#{addBean.doSomething}" /&gt;
         &lt;/h:form&gt;
     &lt;c:when&gt;
  &lt;/c:choose&gt;
  </code></pre>
  
  <p>When I move <code>&lt;h:form&gt;</code> into first <code>c:when</code>, then the action method is called. Otherwise, it isn't. Why?</p>