Custom Handlers for Listers: inactive

This event indicates that the cache this custom handler is attached to is
no longer active (visible in the lister).

The message arguments are:-

        Arg0 - "inactive"          (a string indicating the event type)
        Arg1 - <handle>            (lister handle)
        Arg2 - <title>             (cache title)
        Arg3 - undefined
        Arg4 - <path>              (path of the lister)

This message is caused by the cache in the lister being changed (either by
the user or under rexx control), or even by the lister being closed. Note
that you may receive an active message for another cache with a custom
handler, or even for the same cache, immediately after receiving an
inactive message.