Rated 4 out of 5 stars
There seems to be a change in how restartless Add-ons are called / started since 2012-03-20. Before (Mar.19) it worked as advertised, but since then it's not starting any more. bootstrap.js is loaded, compartment is created, but then, nada.
Seems to be a jetpack issue. Aurora (Fx13) and Beta (Fx12) is fine.