CKFInder 2.3 open folder by default does not work?

Hi,

I'm using the following code:

var finder = new CKFinder({
selectActionFunction : SetFileField,
rememberLastFolder : false,
startupPath : "Layouts:/",
startupFolderExpanded : true
});

finder.popup();

The folder is selected as it should, but the subfolders are not opened by default...
Is this a bug? Or am i missing another option?

Thanks in advance!