texts = ExampleData["Text"];
i = 1;
imax = texts // Length;
bottomSeen = False;
Panel[
Column[
{
Button["Next page", i++; bottomSeen = False;,
Enabled -> Dynamic[bottomSeen]],
Pane[
Column[
{
Dynamic[ExampleData[texts[[i]]]],
,
DynamicWrapper["SEEN THIS", bottomSeen = True]
}],
ImageSize -> {500, 150}, Scrollbars -> True
]
}
]
]