Yep, PowerPack. I also can't get the PP shortcut for embedding to work; add link and add bookmark shortcuts do work. Not a big deal, am getting this straight before I really have a burning need to embed a website, but aggravating I can't figure out what to change to make it work like it should.
Stop the presses: just found a space before frameborder that did not belong. Removing it makes the embed work. Will keep tweaking with the keystrokes part of it, but for now, false alarm. Maybe.