a4j question

[black-white]

hello all,

in my commandbutton below, if i use directly "true" for "rendered"
attribute, it works and calls task.changeDescription method.

however, if i render this command button according to a condition, the
button appears if task.editable is true but the button does not work, i
mean it does not call action method when i press.
<a4j:commandButton id="cb" value="save"
rendered="#{task.editable}" action="#{task.changeDescription}"
reRender="peopleList"/>

do you have any idea what is wrong?

thanks and regards...