Delayed Mouse Tracking

HTML

<!-- error ocurs only in ie7, first add 2 items, then remove 2 items - it is impossible in ie7 -->

<!-- first required section -->
<script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.12/jquery-ui.min.js" type="text/javascript"></script>
<!-- end of first required section -->

<div id="content" style="width:800px;">
        <div id="tasksContainer">
            <div id="operation">
                <div class="operationItem" style="border:solid 1px gray;">
                    <input 
                        name="ScheduleItems[0].ItemAmount" 
                        type="text"
                        aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa="a2" 
                        aaaaaaaaaaaaaaaaaaaaaaaaaaaa="a1"> <!-- third required section - two long-enough attributes -->
                    <div class="remove" onclick="removeOperation(this);" style="border:solid 1px red; width:50px; cursor:pointer;">remove</div>
                </div>
                
             </div>

        </div>
        <div style="display: block; border:solid 1px green; cursor:pointer;" onclick="addNewOperation()">add new</div>
</div>

JavaScript

//second required section
$(document).ready(function () {
    $('input:text').focus(function () {
        $(this).addClass('focus1');
    }).blur(function () {
        $(this).removeClass('focus1');
    });
});
//end of second required section

function addNewOperation() {
    $('#tasksContainer').append($('#operation').get(0).innerHTML);
}

function removeOperation(removeDiv) {
    var detetedNo = $('#tasksContainer .remove').index(removeDiv);
    $('#tasksContainer .operationItem:eq(' + detetedNo + ')').remove();
}