Short key for looping?

Harmonizing melodies in Hookpad is fun - and relatively easy, especially after reading both Hooktheory e-books. My question is a simple one. Harmonizing a melody cannot without trial (and error), so looping and unlooping chords in the context of the rest of the song is a frequent action. Reaching your cursor every time to the top left spot to loop and unloop… in short, a short key for (un)looping would be handy.