title: All actions uses target="_blank" after click in commandButton with this attribute
body: <p>I have a h:commandButton with an atribute onclick="this.form.target='_blank'" for open a PDF in new tab and it works perfectly, but after this action, all other actions (h:commandLink or h:commnadButton) without target attribute open in new tab too.</p>
  
  <p>fragmat from xhtml file</p>
  
  <pre><code>&lt;h:form&gt;
   &lt;rich:panel header="User Logs Data"&gt;
     &lt;h:panelGrid id="ad" columns="2" columnClasses="fieldlabel,fieldvalue"&gt;
  
        &lt;h:outputText value=" Branch:" /&gt;
        &lt;h:selectOneMenu value="#{userLogsInformationController.branch}"
                              converter="#{bankBranchConverter}"
                              disabled="#{not sec:areAllGranted('SHOW_ALL_OUTWARD')}"
                              onchange="submit()"
                              valueChangeListener="#{userLogsInformationController.handleBranchChange}"
                              style="width : 250px;"&gt;
       &lt;f:selectItem itemLabel="[Select Branch]"/&gt;
       &lt;f:selectItems value="#{userLogsInformationController.branches}" 
                      var="br" itemLabel="#{br.name}"/&gt;
       &lt;/h:selectOneMenu&gt;
    &lt;/h:panelGrid&gt;
    &lt;h:panelGrid columns="2"&gt;
       &lt;h:commandButton value="Report"&gt;
           &lt;f:ajax event="click" execute="@form" listener="#{userLogsInformationController.showReport}" render="@form" /&gt;
       &lt;/h:commandButton&gt;
       &lt;h:commandButton value="Download" 
                        actionListener="#{userLogsInformationController.downloadReport}"
                        onclick="this.form.target='_blank'" ajax = "false"
                        disabled="#{userLogsInformationController.notAbleToPrint}"/&gt;
  
       &lt;rich:messages id="messages" style="padding-left:40px; margin-top: 5px"/&gt;
     &lt;/h:panelGrid&gt;
    &lt;/rich:panel&gt;
   &lt;/h:form&gt;
  </code></pre>
  
  <p>I have researched <a href="https://github.com/primefaces/primefaces/issues/2164" rel="nofollow noreferrer">some issues</a> and found that for the first time, target equals _blank it's added to the form as attribute. Second time, target="_blank" is still present in form, while it shouldn't (target parameter is undefined at this point).</p>
  
  <p>I am not getting the solution and cant able to add the method in the page. Need some guide on how to fix this issue.</p>