I am encountering an irritating feature of Lion.
Say I spend 30 minutes in XCode, then I go to iChat to talk to my girlfriend for 5 minutes, then I switch to Safari to check StackExchange, gmail, and whatever else I might want to check.
Then I switch to Safari where I run another set of pages. For 5 or 10 seconds, the app resumes with beachball. This is annoying as hell (switch appnames around, they behave the same).
How can I prevent this from happening at all (unlikely) or at least mitigate it by making a list of apps that are not allowed to go into silently-killed mode?