you are supposed to use database control in 10g, the Web administration interface
Yeah I know, & it's very good - but why give us OEM (even with its missing features) if we're supposed to be using DBConsole?

OK, so earlier versions of Oracle don't support DBConsole which is why we still have OEM, but then the next question is (again!) why release 10g OEM with less functionality than the previous versions? Even if I use it to access my 9i databases I still can't see the locks.