This may be actually be a bug, but I found that on line 330 of includes/admin.toolbar.base.css there are style declaration calls dependent on the id built by the number of tabs associated in the menu.

here is what is currently present.

div#admin-toolbar.vertical div.admin-blocks-1 div.admin-block { top:30px; }
div#admin-toolbar.vertical div.admin-blocks-2 div.admin-block { top:60px; }
div#admin-toolbar.vertical div.admin-blocks-3 div.admin-block { top:90px; }
div#admin-toolbar.vertical div.admin-blocks-4 div.admin-block { top:120px; }
div#admin-toolbar.vertical div.admin-blocks-5 div.admin-block { top:150px; }
div#admin-toolbar.vertical div.admin-blocks-6 div.admin-block { top:180px; }
div#admin-toolbar.vertical div.admin-blocks-7 div.admin-block { top:210px; }
div#admin-toolbar.vertical div.admin-blocks-8 div.admin-block { top:240px; }
div#admin-toolbar.vertical div.admin-blocks-9 div.admin-block { top:270px; }
div#admin-toolbar.vertical div.admin-blocks-10 div.admin-block { top:300px; }

If you end up having more than 10 tabs in the admin menu their subsequent content will not display do to the lack of absolute positioning for the top style.

i fixed this by adding this to the style sheet

div#admin-toolbar.vertical div.admin-blocks-11 div.admin-block { top:330px; }
div#admin-toolbar.vertical div.admin-blocks-12 div.admin-block { top:360px; }
div#admin-toolbar.vertical div.admin-blocks-13 div.admin-block { top:390px; }
div#admin-toolbar.vertical div.admin-blocks-14 div.admin-block { top:420px; }
div#admin-toolbar.vertical div.admin-blocks-15 div.admin-block { top:450px; }
div#admin-toolbar.vertical div.admin-blocks-16 div.admin-block { top:480px; }
div#admin-toolbar.vertical div.admin-blocks-17 div.admin-block { top:510px; }
div#admin-toolbar.vertical div.admin-blocks-18 div.admin-block { top:540px; }
div#admin-toolbar.vertical div.admin-blocks-19 div.admin-block { top:570px; }
div#admin-toolbar.vertical div.admin-blocks-20 div.admin-block { top:600px; }

but im not a fan of editing to the base module. Is this something that has been fixed or corrected in some other way in later versions?