I assume the esteemed reader has already seen a scrollbar. In HTK (and Tk), once you created a scrollbar you will need to connect it to the widget you want to scroll. This is done with the class ScrollBar.html#ScrollBar.HasScrollerHasScroller: you create a scroll bar, and attach it to the scrollable widget with scrollbar option. The example below shows how. Don't forget to pack both the scrollable widget and the scrollbar.