This seems to be variable and also affects things like an edit being made to a Subject.
Sometimes that goes through and the new subject is there when the page comes back; other times it's not and a page refresh is needed.
I use different OS's and different browsers (Safari (Mac); Firefox; Chrome; IE6, 7 and 8) so which browser it is MIGHT be affecting how this works, but I can't say that I've ever connected what happens (or doesn't happen) with a particular browse