pivot creation at runtime

Hi, 
I have a problem when creating pivot in runtime.
This is my code. As you can see, I have this variable x. I want to create grid on runtime and user can create pivot as many as he wanted. The grid and charts are showing properly but only the last grid is editable. User can only change the filter, etc in the last grid created. the first grid is not clickable and editable. How should I fix this?
 
pivot[x] = new Flexmonster({
container: "pivot-container" + x,
licenseKey: "xxx",
componentFolder: "assets/plugins/flexmonster/",
width: "100%",
height: 430,
toolbar: true
});
var flex = {
"dataSource": {
"type": "json", "data": JSON.parse(obj.content)
},
"options": {
"defaultDateType": "date string"
}
};
pivot[x].setReport(
flex
);