Firfox.....hitTest issue?

I have a site that has to have a custom cursor. I’m using an LGUI for the site…though I don’t believe that is related. Basically the custom cursor works perfectly in IE and Safari in that the custom cursor only appears when the user is within the browser window (disappears as user moves to buttons and navigations)…and appears and replaces the default when the user moves back into the browser window…

However, in Firefox the custom cursor will not disappear when the cursor leaves the browser window to the top (it will right, left and bottom)…instead the custom cursor icon snaps to the last known y coordinate and a consistent x coordinate…

In my functions

ringcursor._x = (_xmouse);
ringcursor._y = (_ymouse);

and on a movieclip:

if(this.hitTest(_root._xmouse,_root._ymouse,true)) {
_root.ringcursor._visible = true
}else{_root.ringcursor._visible = 0

While it may not be the most efficient manner…it works flawlessly in IE and Safari and on three sides of a firefox browser window (bottom, left and right). I’m baffled at this point.

Any help would be greatly appreciated.