We could use a sprite for the screen options up/down arrows.
Right now we toggle the URLs directly in JavaScript, and that won’t work in the the new 3.1 subdirectory admin areas in 3.1: personal dashboard (wp-admin/user/) and network admin (wp-admin/network/). So I’d like to be able to agnostically adjust the background position as a solution. Reference: https://core.trac.wordpress.org/ticket/15163#comment:3.