CellWidget not getting displayed

I am trying to make a basic cellbrowser widget work in my App. For now just the Structure so that I can replace it later with something meaningfull. I looked up the samples and implemented one however when I try integarting it in my Application, it wont work!

Here is the part of code. What is the problem? Why cant I see the widget?

public class ListViewImpl extends Composite implements ListView
{

private static ListViewImplUiBinder uiBinder = GWT
        .create(ListViewImplUiBinder.class);

interface ListViewImplUiBinder extends UiBinder<Widget, ListViewImpl>
{
}

private Presenter presenter;

@UiField(provided=true)
CellBrowser cellbrowser;

public ListViewImpl()
{ 
    TreeViewModel model = new ListTreeViewModel();
    cellbrowser=new CellBrowser(model,null);
    cellbrowser.setKeyboardSelectionPolicy(KeyboardSelectionPolicy.ENABLED);
    cellbrowser.setAnimationEnabled(true);
    initWidget(uiBinder.createAndBindUi(this));
}

@Override
public void setPresenter(Presenter presenter)
{
    this.presenter=presenter;
}

 @Override
  public Widget asWidget() {
    return this;
 }

}

The Uibinder file goes as -->

<ui:style>
      .browser {
    border: 1px solid #ccc;
}

.out
 {
        outline:#ccc solid thick;
 }
</ui:style>

    <g:HTMLPanel styleName='{style.out}' >    
                <c:CellBrowser addStyleNames='{style.browser}' defaultColumnWidth='300'  ui:field='cellbrowser'  />
    </g:HTMLPanel>

The ListTreeView model class is perfect as when I use the code in a standalone application and add CellBrowser to RootLayoutPanel. It works!

CellBrowser is a RequiresResize widget (it uses a SplitLayoutPanel internally), so just like with all RequiresResize widget, you have to either put it within a ProvidesResize widget, or give it explicit dimensions.