DIV falling below other DIV in CSS layout
#twitter{
width: 260px;
margin-bottom: 20px;
height: 290px;
overflow: auto;
font-size: 11px;
background: #ececec;
}

<div wrapper></div>
<div wrapper2>
   <div twitter style="float:right"></div>
   <div box1></div>
   <div box2></div>
   ...
</div>