dialog and jquery 1.4 not working correct

if I attach a dialog to a div and open the dialog via onclick the dialog opens, after closing the dialog and doing the same click the dialog does not open again - under jquery 1.3.2 there was no problem.

the dialog is created with following code:

$self = $("<div></div>").attr("id", "gallery_dialog").css("display", "none");
			$(document.body).prepend($self);
			 $("#gallery_dialog").dialog({
				autoOpen:false,
				width:750,
				height:500,
				modal:false,
				hide: "blind",
				resizable:true, // note: if true, we have to resize the inner iframe on the fly
				overlay: {
					background: "#000",
					opacity: 0.8
						}
			});

and opened via clickevent:

$(".pic").live("click",function(){
   $("#gallery_dialog").dialog("open");
});