WidgetInfo button_1 = panel.getChildrenWidgets().get(0);
WidgetInfo button_2 = panel.getChildrenWidgets().get(1);
assertTrue(isVisible(button_1));
assertFalse(isVisible(button_2));
// do MOVE
panel.command_MOVE2(button_2, button_1);
frame.refresh();
assertEditor(
"public class Test implements EntryPoint {",
" public void onModuleLoad() {",
" RootPanel rootPanel = RootPanel.get();",