I use BuddyPress 2.0.1 with WordPress 3.9.1. My site http://zjubot.org/ is enabled admin bar for all users. When users aren’t logged in, there should be items for log in and register in admin bar. There is also a search input.
But when view it in mobile browser, or small window desktop browser, the admin bar is blank for non-logged-in users. That is really bad for user experience.
It is caused by some default CSS settings of admin bar. Hope this can be fixed.