Months ago I saw a guy running commands from a small, text-box-like window, showing nothing else other than the text-box for you to write the command. Such text-box would popup by pressing some keyboard shortcut. Specifically, from what I remember, he was using Lubuntu, and mostly opening apps (like Chrome, Audacious, etc.).
I've never found anything like it, and I've searched considerably for it.
Is it a known extension for lxde or did he most probably create it by himself?