This code will remove the 'Mark All Boards As Read' link that appears in the top bar just below the banner.

<script>
/*Remove Mark All Boards As Read Link
Created By Wrighty*/

var a = get('pms','id').firstChild;
a.firstChild.nextSibling.nextSibling.style.display = 'none';
a.innerHTML = a.innerHTML.replace(/ :: /g,'');
</script>

Global Header