I noticed this by accident a little earlier today and looked into it a bit. Originally I thought it was a bug, but after looking into it a little bit I think its just a feature.
When you start a Unity desktop, Nautilus gets started with the -n parameter to manage the desktop. This "feature" allows you do do a quick search for desktop items. This is where the little search box comes from. If you kill nautilus then this search bar will not come up any more. I'm adding a screenshot to demonstrate how it works. If you don't have any files or folders on your desktop - add a few to play around with it. Then, click on the background(make sure "Desktop" is in focus) and start typing. It does a quick search on any of the files/folders that you have on your desktop. ** Attachment added: "Searching for "test" on my desktop" https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/840821/+attachment/2813035/+files/TypingOnDesktop.png -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/840821 Title: Typing on the desktop brings up a search window in the lower right corner To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/840821/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
