delete key on usb keyboard for macbook pro suddenly triggers launchpad
For about a week now, whenever I hit the delete key on my aluminum usb keyboard, it brings up the launchpad. This doesn't happen when I use the macbook built-in keyboard. It also doesn't happen when I use a different user account. I've tried restoring all the keyboard shortcuts to default, but nothing changes. Any advice?
MacBook Pro with Retina display, OS X Yosemite (10.10.3)