Awesome, thanks!  But what are the (3 at 3)'s for?

On Tue, Aug 20, 2013 at 3:54 PM, Bob Arning <arning315 at comcast.net> wrote:
> how about this
>
> {
> self rowAtLocation: self topLeft + (3 at 3).
> self rowAtLocation: self bottomLeft + (3 at 3 negated)
> }
>
> where self is the PLM
>
> Cheers,
> Bob
>
> On 8/20/13 4:37 PM, Chris Muller wrote:
>
> in a PluggableListMorph.  Say, there are 100 items in the list, but I
> want to identify just the ones that are visible within the scroll
> range.
>
> Any way to do that?
>
> Many thanks..!
>
>
>
>
>
>