RE: C-u with mouse event is ignored?

[Drew Adams]

    > rather than to command `test'. This didn't occur to me - this
    > is the first time I've noticed a difference between 'ignore
    > and nil as a key binding (the latter being actually an unbinding).

    There are other cases where nil and `ignore' behave
    differently: an `ignore'
    in a buffer-local map will shadow a global binding where a nil will not.

    There are also cases where a nil binding is not the same as no-binding
    at all.  IIRC the difference is that a nil binding shadows a binding in
    a parent map.

Thanks. I later figured out the part about ignore shadowing a global
binding, but I wasn't aware of the last part (nil shadowing a parent-map
binding).