> Chrome doesn't require to restart when installing an extension (even if Firefox starts moving to this too)
Mozilla did introduce an api to do restart-less addons about two years ago, as a side effect these addons don't depend on specific firefox versions anymore.
The problem with firefox addons is that they have always hooked directly into XUL, a layout language used inside firefox, which changes (nearly) every version. This means addons needed to be updated regularly. However it did allow them many capabilities (that I suspect the new api doesn't give them).
Mozilla did introduce an api to do restart-less addons about two years ago, as a side effect these addons don't depend on specific firefox versions anymore.
The problem with firefox addons is that they have always hooked directly into XUL, a layout language used inside firefox, which changes (nearly) every version. This means addons needed to be updated regularly. However it did allow them many capabilities (that I suspect the new api doesn't give them).