Hi. I recently had the same question and reached out to JMP support (credit to Jasean). Their solution is shown below, and I just wanted to share in case anyone else encounters this. Basically: you can't control scroll position in a TableBox, but you can with a VScrollBox. So, turn off scrolling in the TableBox, and enclose the table box in a VScrollBox instead.
Names Default to Here(1);
long_lis = {};
for each({i}, 1::100, InsertInto(long_lis, "Item " || Char(i)));
scb = StringColBox("Long List", long_lis);
tbl = TableBox(scb);
tbl << Set Scrollable(0, 0); //Turning off scrolling in the tbl box
tbl << Set Selectable Rows;
goto_bb = ButtonBox("Go To Item",
toSelect = neb << Get;
ItemCount = NItems(long_lis);
tbl << Set Selected Rows(EvalList({toSelect})); // select desired item
{h_extent, v_extent} = vsb << Get Scroll Extents; // in pixels
// determine portion of list above selected item and scroll to that relative position
portion = toSelect / ItemCount;
if(portion < 0.05, portion = 0);
vsb << Set Scroll Position(0, portion * v_extent); // in pixels
);
winny = NewWindow("test",
goto_bb, neb = Number Edit Box(50),
vsb = VScrollBox(Size(360), tbl) // set the size as number of pixels
);
I agree it's not as clean as having the control built-in directly to TableBox, but it works. Hope this helps.
-nikles