Double Submit Bug in Palette?

[Michael Mosmann]

Hi,

i wonder, if i do something wrong. But first the Code:

----------------------------------------------------
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;

import org.apache.wicket.extensions.markup.html.form.palette.Palette;
import org.apache.wicket.markup.html.WebPage;
import org.apache.wicket.markup.html.form.Button;
import org.apache.wicket.markup.html.form.ChoiceRenderer;
import org.apache.wicket.markup.html.form.Form;
import org.apache.wicket.model.IModel;
import org.apache.wicket.model.Model;

public class TestPalettePage extends WebPage
{
  enum TestEnum  {  E1,E2,E3,E4 };
  
  IModel<List<TestEnum>> _model=(IModel<List<TestEnum>>)(new Model(new
ArrayList(Arrays.asList(TestEnum.values()))));

  IModel<Collection<TestEnum>>
_choices=(IModel<Collection<TestEnum>>)(new Model(new
ArrayList(Arrays.asList(TestEnum.values()))));

  
  public TestPalettePage()
  {
    Form form=new Form("form")
    {
      @Override
      protected void onSubmit()
      {
        System.out.println("Selected: "+_model.getObject());
      }
    };
    
    ChoiceRenderer<TestEnum> choiceRenderer=new
ChoiceRenderer<TestEnum>("name","ordinal");
    Palette<TestEnum> palette=new
Palette<TestEnum>("palette",_model,_choices,choiceRenderer,3,true);

    form.add(palette);
    form.add(new Button("submit"));

    add(form);
  }
}
----------------------------------------------------

In this example onSubmit is called twice. The second time the output is
  "Selected: []"
which is wrong.

Bug?
We are using 1.4-rc2, but the same error exist in 1.4-rc1 and 1.3.5.

Thanks.
mm:)