When a multisite installation has too many sites in the "My sites" quick access dropdown menu (ie, 23 sites in a 1366x768 resolution) the menu becomes longer than the fold. When scrolling the page, the menu is in fixed position and its content doesn't scroll. So, sites that are below the fold cannot be accesed via this dropdown.
This is a minor issue, since there is a workaround: clicking "My sites" will take you to a list of sites and so one can access the 24th site and those below it. But still, it is an issue, since the admin bar should be usable in every situation.
I found a topic describing this very issue: http://wordpress.org/support/topic/list-of-sites-from-admin-bar-in-multisite-wont-scroll
Topic was posted a year ago and now is closed. There's no bug tracking detailed. Does anyone know if this has been formally reported? If not, how can it be done?