The VerticalSplitPanel lets the user move the divider between two cells aligned vertically. The split is horizontal, the cells are aligned vertically. You get scrollbars if the content disappears under the edge of the cell.
String lorem = "Lorem ipsum dolor sit amet...";
VerticalSplitPanel panel = new VerticalSplitPanel();
panel.addStyleName("demo-VerticalSplitPanel");
panel.setSize("550px", "300px");
panel.addStyleName("demo-panel");
panel.setTopWidget(new HTML(lorem));
panel.setBottomWidget(new HTML(lorem));
RootPanel.get("demo").add(panel);
.VerticalSplitPanel .vsplitter
{
background-color : #00f;
/* Pretty much everything */
cursor : n-resize;
/* IE6, IE7, FF2, Safari Win */
cursor : row-resize;
}