c8fee158_pl____h_selectBooleanCheckbox___Description
[Name] immediate [Type] boolean [Supports EL?] Yes [Description] 
A boolean value that identifies the phase during which action events should fire. During normal event processing, action methods and action listener methods are fired during the "invoke application" phase of request processing. If this attribute is set to "true", these methods are fired instead at the end of the "apply request values" phase.
Apache MyFaces JSF-2.0 Core Impl - <h:selectBooleanCheckbox>