I noticed that for some reason, I wasn't having the same problem as you after the upgrade, so I did a little digging, and (assuming you haven't figured out a workaround already) I put together what I did that got rid of the header bar.
First of all, if you want the bar gone for the entire duration of the game, the best place to put it is in the start script for the game, which you can find under the "scripts" tab while you're looking at the game object (or if you're in code view, it's the "start" attribute). But that just gets rid of the text, to get rid of the blue bar, you need to insert an html file, which is also best in the start script for the game.
All together, in code view that's:
<game name="Example">
<start type="script">
insert ("Test.html")
request (Hide, "Location")
</start>
</game>
And the html file should look like this:
<html>
<head>
<style type="text/css">
.ui-widget-header
{
border: none;
background: transparent;
}
</style>
</head>
</html>
Hope I've helped!