The following code:

Code:
        Viewport viewport = new Viewport();
        viewport.add(new ContentPanel(), new MarginData(10));
        viewport.add(new Button("Button 1"));
        RootPanel.get().add(viewport);
is failing with the message and stack:

00:15:59,469 [ERROR] Rebind result 'com.sencha.gxt.theme.base.client.container.ViewportBaseAppearance' has no default (zero argument) constructors.
java.lang.NoSuchMethodException: com.sencha.gxt.theme.base.client.container.ViewportBaseAppearance.<init>()
at java.lang.Class.getConstructor0(Class.java:2721)
at java.lang.Class.getDeclaredConstructor(Class.java:2002)
at com.google.gwt.dev.shell.ModuleSpace.rebindAndCreate(ModuleSpace.java:463)
at com.google.gwt.dev.shell.GWTBridgeImpl.create(GWTBridgeImpl.java:49)
at com.google.gwt.core.client.GWT.create(GWT.java:97)
at com.sencha.gxt.widget.core.client.container.Viewport.<init>(Viewport.java:47)
the source is taken from javadoc so I'm not sure what is wrong:
out of date documentation or buggy code... or maybe I miss something.

I use GXT 3.0 dp5