Did you try to remove browser cache?
Stephan,
This was not the solution.
The source of the login page: <html> <head> <title>Speelplaatsbeheer</title>
<!-- keeping IE8-9 in standards mode -->
<meta http-equiv="X-UA-Compatible" content="IE=edge;chrome=1" />
<meta http-equiv="expires" content="0" />
<meta http-equiv="pragma" content="no-cache" />
<link type="text/css" rel="stylesheet" href="mxclientsystem/mxui/ui/mxui.css" media="screen"/>
<link type="text/css" rel="stylesheet" href="ui/theme-custom/layout.css" media="screen"/>
<!--[if IE 6]>
<link type="text/css" rel="stylesheet" href="ui/ie6/banner.css" media="screen"/>
<![endif]-->
<script type="text/javascript" src="mxclientsystem/dojo/dojo.js"
djConfig="
rtlRedirect: 'index-rtl.html'
">
</script>
</head>
<body class="tundra default">
<div dojoType="dijit.layout.BorderContainer"
design="headline"
gutters="false"
id="mainbox"
class="MxClient_mainContainer"
>
<div dojoType="dijit.layout.ContentPane"
region="top"
id="topPane"
class="MxClient_topPane"
>
<div class="MxClient_headerPane">
<div class="MxClient_logoPane png"></div>
<div class="currentUserDiv">
<div dojoType="mxui.widget.ThemeSwitch" themes="Custom" label="Kies uw layout:"></div>
<div class="log"> | <a href="javascript:void(0);" id="log_out"></a></div>
</div>
</div>
<div class="navigationPane_bg">
<div class="MxClient_navigationPane">
<div class="MxClient_loader" id="MxClient_loader"></div>
<div dojoType="mxui.widget.Toolbar" id="MxClient_toolbar" class="MxClient_toolbar"></div>
<div dojoType="mxui.widget.Navbar" id="MxClient_navbar" class="MxClient_navbar"></div>
</div>
</div>
<!--<div dojoType="mxui.widget.TitlePath" id="MxClient_titlepath" class="MxClient_titlepath"></div>-->
</div>
<div dojoType="dijit.layout.BorderContainer"
region="center"
design="sidebar"
liveSplitters="false"
class="MxClient_contentContainer"
>
<div dojoType="mxui.widget.ScreenBuffer"
region="center"
id="contentPort"
class="MxClient_contentPane"
>
</div>
</div>
<div dojoType="dijit.layout.ContentPane"
region="bottom"
class="MxClient_bottomPane"
>
<div class="MxClient_footerPane">
Powered by <a target="_blank" href="http://www.csmsolutions.nl">CSM Solutions</a>
</div>
</div>
</div>
<!--[if IE 6]>
<div id="ie6banner" class="ie6banner" style="display:none">
<img src="ui/ie6/ie6banner.png" width="280" height="90" border="0" usemap="#ie6banner" />
<map name="ie6banner">
<area shape="rect" coords="35,34,75,74" href="http://www.mozilla-europe.org/" target="_blank" title="Mozilla Firefox" />
<area shape="rect" coords="82,34,122,74" href="http://www.google.com/chrome/" target="_blank" title="Google Chrome" />
<area shape="rect" coords="129,34,169,74" href="http://www.apple.com/safari/" target="_blank" title="Apple Safari" />
<area shape="rect" coords="176,34,216,74" href="http://www.microsoft.com/windows/internet-explorer/default.aspx" target="_blank" title="Microsoft Internet Explorer" />
</map>
</div>
<![endif]-->
<script type="text/javascript" src="mxclientsystem/mxui/mxui.js"></script>
<script type="text/javascript">
(function() {
var btn = document.getElementById("log_out");
dojo.connect(mx.ui, "startup", function() {
btn.innerHTML = mx.session.isGuest() == true ? "" : "Log out";
});
dojo.connect(btn, "click", function() {
mx.session.logout();
});
})();
</script>
</body>
</html>