The 'setTitle' method can change the title of a window component. Please check your code carefully.
Here is my code for opening the window and centering it on screen.
$('#popUpForm').load('../ajax/skiftArbejdstid.php', {
medarb1: node.id,
medArbNavn1: node.navn,
getDate: getDate,
klokken: getTime
}, function() {
$('#popUpForm').window('setTitle','Skift arbejdstid');
$('#popUpForm').window('open');
$('#popUpForm').window('center');
});
And here is my init of the window
<div id="popUpForm" class="easyui-window" style="width:750px;height:700px"
data-options="modal:true, left:-1000,top:-1000, closed:false">
<div class="easyui-layout" data-options="fit:true">
</div>
</div>