I love what this application can do when I need it to proof things, but the darn app slows down my entire system in 10.4.11 and can create spinning beach balls galore. I'm in Safari and the app starts with a hot key, but Safari just chokes. I've noticed this problem in many apps. Spell Catcher, which doesn't have all the features of Grammarian, but doesn't cause these types of systemic problems.