How do I make my page header static again?

[Ste DB]

Hi

After Confluence upgrade to 6.6.1 version I found this new "breadcrumb/edit/share" little header while scrolling down and up again.

Before upgrade, I applied a css to main-header and title-heading in one Space in order to have particular colours, font and some info/button hidden.
A sample:

All pages are displayed in a custom browser (not official IE, nor Firefox, Chrome, etc...) built into a program.

It worked perfectly under previous version (5.8.x).
This new "breadcrumb/edit/share" little header, makes a disaster while scrolling, in both "custom" and "official" browsers.

• the small celeste bar still appears while scrolling down (blue bigger bar correctly hidden).
• nothing appears, never more, if I stop and then restart scrolling down.
• nothing appears, never more, when I scroll up, even coming back at the page top.

I understood that, while scrolling, main-header style changes to "position:fixed; top:-50px" so I even tried to apply a little javascript (in a user-macro) to block main-header position while scrolling, but doesn't work:

<script>
window.onscroll = function() {
 document.getElementById("main-header").style.top = "0px";
 document.getElementById("main-header").style.position = "static";
 document.getElementById("title-heading").class="pagetitle";
}
</script>

Anyone has any idea about how to restore the original behavior, making page header static again? Please let me know. 

Thank you.