The header columns in a combo grid initially have a wrong size (very small) when no width is given in the column definition (with fitColumns = true).
After a reload data or when using the pagination controls the header columns are resized to fit the content correctly.
This can be shown with the combogrid demo (
http://jeasyui.com/demo/main/index.php?plugin=ComboGrid&theme=default&dir=ltr&pitem=) by removing the width attributes as follows:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Basic ComboGrid - jQuery EasyUI Demo</title>
<link rel="stylesheet" type="text/css" href="easyui.css">
<link rel="stylesheet" type="text/css" href="icon.css">
<link rel="stylesheet" type="text/css" href="../demo.css">
<script type="text/javascript" src="jquery-1.10.2.js"></script>
<script type="text/javascript" src="jquery.easyui.min.js"></script>
</head>
<body>
<select class="easyui-combogrid" style="width:400px" data-options="
panelWidth: 500,
idField: 'itemid',
textField: 'productname',
url: 'datagrid_data1.json',
method: 'get',
showFooter: true,
columns: [[
{field:'itemid',title:'Item ID'},
{field:'productname',title:'Product'},
{field:'listprice',title:'List Price',align:'right'},
{field:'unitcost',title:'Unit Cost',align:'right'},
{field:'attr1',title:'Attribute'},
{field:'status',title:'Status',align:'center'}
]],
fitColumns: true
">
</select>
</body>
</html>
