void DropSum(int ii, PasteClip& d) {
if(AcceptInternal<ColumnList>(d, "mydrag")) {
const ColumnList& src = GetInternal<ColumnList>(d);
int sum = 0;
for(int i = 0; i < src.GetCount(); i++)
if(src.IsSel(i))
sum += atoi(~String(src[i]));
list.Set(ii, AsString(sum));
d.SetAction(DND_COPY);
list.SetCursor(ii);
}
}
