final HTML north = createHTML("North", "#cacaf7");
dock.addNorth(north, 100);
final HTML south = createHTML("South", "#ccffcc");
dock.addSouth(south, 100);
final HTML east = createHTML("East", "#ffcccc");
dock.addEast(east, 100);
final HTML west = createHTML("West", "#ffff99");
dock.addWest(west, 100);
FlowPanel buttons = new FlowPanel();
ToggleButton button = new ToggleButton("Hide North", "Show North");