[X4U] application switching hangs often

[Xavier Noria]

I have a MacBook with an up-to-date system, and application switching  
(what Command-Tab triggers) hangs often. Say once every fortnight. I  
have run repair permissions several times, and even rebuilt  
everything with the recently released DiskWarrior 4, just in case. No  
luck, it just happened today again.

Is this a known issue? Sometimes I have ssh access to the laptop from  
another machine, I tried to kill the Finder and the Dock to no avail,  
do you know a way to resurrect the machine from a shell without  
rebooting?

-- fxn