While testing some ideas for a jukebox application for my “media center” computer, I came to a point, where the user should be able to select an interpret or song from a huge list. If he knew the exact name, scrolling through a sorted list should be ok, but still a way to narrow the list by typing some initial letters would be much faster and convinient. This should not be difficult on a thouch screen, but as I also wanted this application to work on mouse-only devices, as a keyboard was for example too space consuming in my configuration. So I ended up trying to find an interface component, allowing an user to enter a view letters with a pointing device like a mouse or a track ball.
It is basically a pop-out technique, but making use of moving the mouse pointer in two dimensions, than the common linear approach. Operatiing this first prototype version on the left is still a little rough though.