extendedSettingsPanel.setClosed();
final GridBuilder innerGridBuilder = extendedSettingsPanel.createGridBuilder();
innerGridBuilder.newSplitPanel(GridSize.COL50);
{
// Gantt object type:
final FieldsetPanel fs = innerGridBuilder.newFieldset(getString("gantt.objectType"));
final LabelValueChoiceRenderer<GanttObjectType> objectTypeChoiceRenderer = new LabelValueChoiceRenderer<GanttObjectType>(fs,
GanttObjectType.values());
final DropDownChoice<GanttObjectType> objectTypeChoice = new DropDownChoice<GanttObjectType>(fs.getDropDownChoiceId(),
new PropertyModel<GanttObjectType>(data, "ganttObjectType"), objectTypeChoiceRenderer.getValues(), objectTypeChoiceRenderer);
objectTypeChoice.setNullValid(true);