How to set Dialog height to auto?

How to set Dialog height to auto?


Hi, here there's a test of the dialog plugin.
http://lab.gianiaz.com/jquery/dialog/
I've tried with this init options:
var dOffset = $('#dialogContent').offset();
$('#dialogContent').dialog({
buttons: {
'Okay': function() {
$('#dialogContent').dialog('close');
}
},
modal : true,
height: 'auto'
});
But with height auto the content is displayed also under the
button_pane.
How can I say to the plugin to resize in the correct way?
Another question about dialog, I've seen the "overlay" option, but I
can't understand how to use it, there's an example to look at?
Thank you