I agree, but Lucas never explained if Qui-Gon learned this secret about staying around as a Force ghost and taught it to Yoda, who taught it to Obi-Wan just before they both went into exile, how would Anakin know about it? And why didn't Qui-Gon disappear (of course, that's fixable, but Obi-Wan would have freaked out next to that pit if he had never seen that before).
It's all sloppy. All Jedi should have disappeared when they died. Then nothing would be wrong. I'm still upset about that.