Problem with Droppable

Problem with Droppable


Hello there,
this is my first post to this group - i hope i will be able to
contribute in the future, but today i will need your help.
I´m defining a droppable as follows:
/* sth before */
$(".gastcontainer").droppable({
        accept: ".gast",
        activeClass: 'droppable-active',
        hoverClass: 'droppable-hover',
        drop: function(ev, ui) {
            oldParent = ev.target.parentNode
            if(calcRoomFigures(this)) { // does some further evaluation
                $(this).append(ui.element)
                $(ui.element).css({position: 'static'})
                updateRoomFigures(this)
                /* #1 */
                if($(oldParent).hasClass("gastcontainer")) {
                    updateRoomFigures(oldParent)
                    return
                }
            } else {
                $("#gastliste").append(ui.element)
                $(ui.element).css({position: 'static'})
                zimmer = $(this).parents("div.zimmer")[0]
                zm_name = $($(zimmer).find("div.info span.zimmername")[0]).html()
                $("#messages").text(zm_name + " ist voll. Bitte die Person in ein
anderes Zimmer stecken.").show("slow")
                setTimeout("hideMessages()", 3000)
            }
        }
    });
/* sth after */
it works great up to #1 when i run it step by step with firebug,
i can see, that the element is added to the droptarget, just as i want
it.
but instead of just stopping here, the browser jumps to jquery-
latest.js line 1997. it there does something i don´t know, and undoes
everything that happened before, and re-attaches the dragged element
to its former parrent.
Any idea on why this happens?
Thanks a lot for your answers,
Frank