It disappeared …
So it seems; it no longer shows up under Management -> Activity Monitor. Even on-line books state it is there.
I still have RC0 and have read on other sides even in RTM. It is in same location …
If you right click on the server, in the pop-up menu we have the “Activity Monitor” option now.
I don’t know why it was moved there; I thought it was good under management. Mind you this does make it easier to get to it now, maybe that why. :).