Please try this example:
<div id="cc" class="easyui-layout" style="width:700px;height:350px;">
<div title="West" style="width:100px;" data-options="
region:'west',split:true,
hideCollapsedContent: false,
onCollapse: function(){
var title = $('#aa').accordion('getSelected').panel('options').title;
$('#titlebar').html(title)
},
collapsedContent: function(){
return $('#titlebar');
}
">
<div id="aa" class="easyui-accordion" fit="true">
<div title="Panel1"></div>
<div title="Panel2"></div>
<div title="Panel3"></div>
</div>
</div>
<div data-options="region:'center',title:'Main Title'">
</div>
</div>
<div id="titlebar" class="panel-title layout-expand-title layout-expand-title-down"></div>