[Groff] chop in pic?

[Larry McVoy]

Folks, consider the following pic.  In the original pic, I believe that I
remember that chop would end the arrows at the boundary of the ellipse but
GNU pic has never done that.  Is this a known bug?  Is my memory/understanding
incorrect?  Thanks.

.sp .5i
.ps 12
.vs 14
.ce 1
Andy's setup version 1.3
.sp
.ft H
.po .6i
.PS
    M: ellipse wid 1.5 ht 1 fill .1 "Main" "level 1"
    move right
    S: ellipse wid 1.5 ht 1 fill .1 "US Main" "level 2"
    arc cw rad 2 from M.ne to S.nw ->
    "clone" at last arc.n + 0,.1
    A: ellipse wid 1.5 ht 1 fill .1 "Merge" "level 1" with .n at M.s - 0,1
    arc cw from M.se to 1/2 between A.n and A.ne -> chop
    " clone" at last arc.e ljust
    arc cw rad 2 from S.s to A.ne ->
    "  pull and merge" at last arc.se ljust
    arc cw from A.nw to M.sw -> 
    " push" at last arc.w ljust
.PE
.ps 
.vs 
.ft
.po