Timeouts for idle webmail users?

[Michael Bull]

I've been tracing the discussions on idle timeouts.   What is the best way 
to implement this?  I've been trying to make some changes with php.ini that 
haven't seemed to work (by setting the session.cookie_lifetime to 900 
seconds, to test).   Should that setting have worked with how 2.3 uses 
sessions with php?  Someone had mentioned about there being the "hooks" for 
where idle timeouts could be in the imp/horde code, but they hadn't been 
implemented.... any thoughts on the best approach for this?