Major Description
The JSF 1.1 specification requires any implementation to support Java 1.3 and that's why the FacesException isn't allowed to utilize builtin exception chaining mechanisms (i.e. initCause(), etc..) as they have been introduced in Java 1.4. However, the FacesException retains it's cause by delegating to the parent's constructor (for example, "super(cause);" or "super(message, cause);").
Although this bug is rather easy to fix, I've assigned the priority level 'Major' as it breaks the specification.