After upgrading to version 1.3.1 the SearchBox does not apply a width attribute to the INPUT tag. This only occurs when no menu is applied. Running the code below will demonstrate this. The first SearchBox displays correctly (with a menu), the second not (without a menu). This was tested in FF, Chrome and IE. All gave the same results.
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>SearchBox - jQuery EasyUI Demo</title>
<link rel="stylesheet" type="text/css" href="http://www.jeasyui.com/easyui/themes/default/easyui.css">
<link rel="stylesheet" type="text/css" href="http://www.jeasyui.com/easyui/themes/icon.css">
<script type="text/javascript" src="http://www.jeasyui.com/easyui/jquery-1.8.0.min.js"></script>
<script type="text/javascript" src="http://www.jeasyui.com/easyui/jquery.easyui.min.js"></script>
</head>
<body>
<input class="easyui-searchbox" data-options="prompt:'Please Input Value',menu:'#mm',searcher:function(value,name){alert(value+':'+name)}" style="width:300px"></input>
<div id="mm" style="width:120px">
<div data-options="name:'all',iconCls:'icon-ok'">All News</div>
<div data-options="name:'sports'">Sports News</div>
</div>
<input class="easyui-searchbox" data-options="prompt:'Please Input Value', searcher:function(value,name){alert(value+':'+name)}" style="width:400px"></input>
</body>
</html>
