SuggestBox in GWT UiBuinder

I am currently working also on a project hosted on Google App Engine (http://appspot.com) and I want to share some tips about some of the frameworks offered by the GAE environment.
Today I want to talk about a problem we had using the GWT SuggestBox component while making UiBinder layouts. The class com.google.gwt.user.client.ui.SuggestBox is a text box or text area which displays a pre-configured set of selections that match the user's input. Each SuggestBox is associated with a single com.google.gwt.user.client.ui.SuggestOracle. The SuggestOracle is used to provide a set of selections given a specific query string. Our application provides a method to retrieve suggestions from the backend while a user writes into the SuggestBox. This worked fine with a GWT Java layout, but moving to UiBinder layout we faced the following problem. We added a SuggestBox to a view through the GWT designer. The code generated was the following:

View.ui.xml:

<g:SuggestBox ui:field="fromSuggestBox"/>

View.java:

@UiField
SuggestBox fromSuggestBox;

Then we added to the View class the method to populate the MultiWordSuggestOracle to be passed to the SuggestBox:
private MultiWordSuggestOracle createOracle() {
        MultiWordSuggestOracle oracle = new MultiWordSuggestOracle();
        ...
        // Code to retrieve values
        ...
        return oracle;
}

So we set the attribute provided to true for the @UiField annotation
@UiField(provided = true)
SuggestBox fromSuggestBox;

and tried to manually create the SuggestBox instance into the constructor of the View class before invoking 
the initWidget method
public Tracking(String firstName) {
        SuggestBox fromSuggestBox = new SuggestBox(createOracle());
        initWidget(uiBinder.createAndBindUi(this));
}


But the application throwed an exception at runtime while rendering the view. This doesn't work. The only way to populate a SuggestBox in a UiBinder view is to create the Suggest Box instance while declaring it

@UiField(provided = true)
SuggestBox fromSuggestBox = new SuggestBox(createOracle());

and not inside the View class constructor.