XPages Button unresponsive after 4 ajax calls - xpages

Question

Maybe I'm going crazy, but I think this is an issue of XPages
I'm working with XPages with Domino 9.0.1 FP3.
It seems that when I do a page that does XPages 4 ajax calls to a xagent, one after the other all the buttons on the page become unresponsive.
Up to 3 ajax calls everything works ... doopo fourth buttons become unresponsive.
Seeing is believing!!!!**
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****This is my example page**:** testPage.xsp
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<? Xml version = "1.0" encoding = "UTF-8"?>
<Xp: view xmlns: xp = "http://www.ibm.com/xsp/core">
<Xp: button value = "Update edit box" id = "button1">
<Xp: EventHandler event = "onclick" submit = "false"
refreshMode = "partial" refreshId = "inputText1">
<xp:this.action><![CDATA[#{javascript:getComponent("inputText1").setValue(session.createDateTime(#Now()))}]]></xp:this.action>
</ Xp: EventHandler> </ xp: button>
<Xp: inputText id = "inputText1"> </ xp: inputText>
<Xp: br> </ xp: br> <xp: button value = "Call for Ajax 3 time (button Work)" id = "button3">
<Xp: EventHandler event = "onclick" submit = "false">
<Xp: this.script> <! [CDATA [for (i = 0; i <3; i ++) {
   dojo.xhr.get ({
  url: "http://app.quattroemme.it/home.nsf/testXagent.xsp"
  handleAs: "xml"
  load: function (data) {
  }
});
}]]> </ Xp: this.script>
</ Xp: EventHandler> </ xp: button>
<Xp: br> </ xp: br>
<Xp: br> </ xp: br>
<Xp: button value = "Call for Ajax 4 time (button unresponsive)" id = "button2">
<Xp: EventHandler event = "onclick" submit = "false">
<Xp: this.script> <! [CDATA [for (i = 0; i <4; i ++) {
   dojo.xhr.get ({
  url: "http://app.quattroemme.it/home.nsf/testXagent.xsp"
  handleAs: "xml"
  load: function (data) {
  }
});
}]]> </ Xp: this.script>
</ Xp: EventHandler> </ xp: button>
</ Xp: view>
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This is the simple xagent I call with ajax (testXagent.xsp)
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// The external context gives access to the servlet environment
var exCon = facesContext.getExternalContext();
// The writer is the closest you get to a PRINT statement
// If you need to output binary data, use the stream instead
var writer = facesContext.getResponseWriter();
// The servlet's response, check the J2EE documentation what you can do
var response = exCon.getResponse();
// In this example we want to deliver xml and make sure it doesn't get cached
response.setContentType("text/xml");
response.setHeader("Cache-Control", "no-cache");
// Here all your output will be written
writer.write("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<christmas date\"24Dec\" />");
// We tell the writer we are through
writer.endDocument();
print ("XAGENT")
facesContext.responseComplete();

Answer 1

Ensure your XAgent's XPage is not set to store the state. That's done by going to the All Properties tab of the Properties panel and, in the Basics section, setting viewState to nostate. Otherwise a component tree for the XPage is stored server-side. There are a fixed number of component trees that can be stored and you can hit that by loading multiple window tabs or repeatedly loading XAgents where viewState has not been overridden. The result is an XPage which is non-responsive to partial refreshes. (Admittedly I always use a partial refresh to call an XAgent, so I'm not 100% sure this will also affect a dojo.xhr.get.)
Keeping a component tree stored server-side is normal behaviour in XPages and required in order for the XPage to be "stateful". Otherwise, the "next" button on a pager would only ever go to page 2, because it doesn't know what page the browser is currently on, only what the default is, i.e. Page 1.

Answer 2

Thanks Paul. I resolve my problem using viewState = nostate.
My problem appears from the use of ExtJs TreeGrid that opens nodes on demand
The TreeGrid uses two xagent that read data from the server and return json that ExtJs use for render tree. When I had to open all the tree TreeGrid automatically made a call to xagent for each node and the buttons have become unresponsive .... !!!!!!! now everything is OK