hello all,
i am super stumped.
i have many elements (floating href tags) in a div with a set height/width, with scroll set to "overflow: auto" in the css.
this is the structure of the divs:
<div id="tagFun_div_main">
<div id="tf_div_tagsReturn">
    <!-- all the draggable elements go in here, the parent div scolls -->
</div>
<div id=" tf_div_tagsDrop">
    <div id="tf_dropBox"></div>
</div></div>
the parent div's, 'tf_div_tagsReturn' and 'tf_div_tagsDrop' will ultimately float next to each other.
here is the jquery which is run after all of the 'draggable' elements have been created with class name 'tag_cell', :
$(function() {
    $(".tag_cell").draggable({ 
        revert: 'invalid', 
        scroll: false,
        containment: '#tagFun_div_main'
    });
    $("#tf_dropBox").droppable({
        accept: '.tag_cell',
        hoverClass: 'tf_dropBox_hover',
        activeClass: 'tf_dropBox_active',
        drop: function(event, ui) {
            GLOBAL_ary_tf_tags.push(ui.draggable.html());
            tagFun_reload();
        }
    });
}); 
as i stated above, the draggable elements are draggable within div 'tf_div_tagsReturn', but they do not visually drag outside of that parent div. worthy to note, if i am dragging one of the draggable elements, and move the mouse over the droppable div, with id 'tf_dropBox', then the hoverclass is fired, i just can't see the draggable element any more.
thank you very much for any advice on helping me find a solution. this is my first run at using jquery, so hopefully i am just missing something super obvious. i've been reading the documentation and searching forums thus far to no prevail :(
thank you for your time.
UPDATE:
many thanks to Jabes88 for providing the solution which allowed me to achieve the functionality i was looking for, here is what my jquery ended up looking like, feel free to critique it, as i am new to jquery. 
$(function() {
    $(".tag_cell").draggable({ 
        revert: 'invalid', 
        scroll: false,
        containment: '#tagFun_div_main',
        helper: 'clone',
        start : function() {
        this.style.display="none";
        },
        stop: function() {
        this.style.display="";
        }
    });
    $(".tf_dropBox").droppable({
        accept: '.tag_cell',
        hoverClass: 'tf_dropBox_hover',
        activeClass: 'tf_dropBox_active',
        drop: function(event, ui) {
            GLOBAL_ary_tf_tags.push(ui.draggable.html());
            tagFun_reload();
        }
    });
});