sticky nav - fixed position is not working

Hi,

I have a rectangle with fixed position, top of 80px, and right of 0px:

var tabs = sym.$("tabs");

tabs.css({"position":"fixed","top":"80px", "right":"0px"});

Inspecting the element in the browser (safari) confirms that the position is fixed.  (Look at the blue rectangle on the right.)  And it does stick to the right side if I change the width of the browser.

However, if I scroll up, the blue box scrolls up and off the stage:

Even though the computed style shows a top of 80px.

Any help would be most appreciated.

Thanks

-Sherry