how to make popup appear to the left of icon

I am using the following code to display a popup anound a icon on mouseover event.

dijit.popup.open({ around: dojo.byId("xxxIcon"), popup: dijit.byId("yyyPopUp") });

This is causing the popup to show below and to the right of the icon "xxxIcon" and also on a system with less screen resolution it is causing a scrollbar to appear.
How can I make the popup to appear on top of the "xxxIcon". also is there a way the popup window will shrink and expand with the page.

I tried adding the following to it.

var s = dijit.byId("popupWindow1").domNode.style;
s.left = "-10px";
s.top = "100px";

and this works in readjusting the popup to the left of the icon, this works on ff and IE6 but not on IE 7.
Please let me know how can this work on IE 7 (make the popup to the below-left of icon instead of below-right)