Why do jsf call my getters infinite time using rich:listShuttle

[ellie spring]

Hi everyone.

I am just wondering if this is a normal behavior in jsf, my getter on my backing bean is called continuously when a request the page that
populates my rich:listShuttle. I have a simple stdout on my getters and it seams there is an infinite call. Is there a way how to prevent this thing because i think
this wastes a lot of cpu memory.

Is there any good explanation on this or am i missing something very important.
Please help me to be enlightened.

Thanks in advance.