jquery - right position and scroll bar in Firefox -

if animate div position right makes strange movement. happens in firefox, if have div positioned right, , if there scroll bar. why happen , how can solve it?

• only firefox
• right position
• with scrollbar

here example simplified check: http://jsfiddle.net/lhaeh/1/

html:

<div id="blue"></div> <div id="red"></div> 

css:

#red {     position: fixed;     bottom: 20px; right: 25px;     width:80px; height:50px;     cursor:pointer;      background:red; }  #blue {/*this div create scroll*/     margin:0 auto;     width:80px; height:500px;     background:blue; } 

jquery:

$(function(){      $("#red").click(function() {         $("#red").animate({bottom:'-80px'},1000);     });  }) 

try position: absolute;.

additional explanation: assume jquery's animate() changes position absolute before starting animation, causes firefox move object bit, instead of leaving was.