Drag N Drop Stops working for some reason in IE 9

Drag N Drop Stops working for some reason in IE 9

I'm a newbie in Jquery. I'm using jquery ui drag n drop (draggable and droppable) jquery-ui-1.10.3.custom.min.js and jquery-1.10.2.min.js, it works , but for some reason it stops working after several seconds when i'm sending some data (using ajax) about columns' position into the server , i can't understand what is the problem and why it stops working (i.e. i can't drag columns with mouse cursor , it only selects text with cursor but doesn't drag the columns). Also i have an issue with helper: "clone" in IE9 it doesn't displays column's header as a clone it only displays plan text without any css, in others webbrowsers it works fine but not in IE 9.


here is my code :


/*======================*/
var initDragNDrop = function () {
$(".available-headers").unbind().on("dblclick", "li", function () {
var columnIndex = $(this).prop("id");
$(this).remove();


$("#tasksTable").dataTable().fnSetColumnVis(columnIndex, true);
saveColumnsChanges();
});


$("#tasksTable").droppable({
drop: function (event, ui) {
if ($(ui.draggable).is("th")) return;
var columnIndex = $(ui.draggable).prop("id");
$(ui.draggable).remove();
$("#tasksTable").dataTable().fnSetColumnVis(columnIndex, true);
saveColumnsChanges();
}
});


$(".available-headers").droppable({
drop: function (event, ui) {
var columnIndex = $(ui.draggable).data().column;
$("#tasksTable").dataTable().fnSetColumnVis(columnIndex, false);
var headers = $(".available-headers #headers");

var hiddenHeader = "<li id='" + columnIndex + "' class='ui-draggable hidden-header'><div class='hidden-header-wrapper'><i class=''></i><span> " + $(ui.draggable).text().trim() + "</span></div></li>";


$(headers).append(hiddenHeader);
saveColumnsChanges();
}
});


var saveColumnsChanges = function () {
var coulmnsIds = '';
$("#headers").children('li').each(function (idx, li) {
var id = $(li).prop("id");
coulmnsIds += id + ",";
});


var colsData = {customColumns : coulmnsIds};
$.ajax({
type: "POST",
url: "/ProjectI/Home/SaveColumns",
data: colsData,
success: function () {
},
error: function () {
}
});

};



$(".available-headers .hidden-header").draggable({
containment: "window",
enable: true,
revert: "invalid",
scroll: false,
appendTo: 'body',
drag: function () {

},
start: function () {
$(this).data("startingScrollTop", $(this).parent().scrollTop());
},
cursorAt: {
top: 0,
left: 0
}
});
$("#tasksTable th").draggable({
enable: true,
containment: "window",
revert: "invalid",
scroll: false,
start: function () {
$(this).data("startingScrollTop", $(this).parent().scrollTop());
$(".available-headers").addClass("draggable-headers");
},
stop: function() {
$(".available-headers").removeClass("draggable-headers");
},
drag: function (event, ui) {
if ($(this).text().trim() == "check") {
$(ui.helper).remove();
$(this).trigger("mouseup");

}
},
helper: 'clone',
appendTo: 'body',
});
};






/*======================*/




Any ideas why it stops working?