public class ExampleForm extends AbstractForm {
	@Override
	protected int getConfiguredDisplayHint() { 
		return IForm.DISPLAY_HINT_VIEW;
	}
	@Override
	protected String getConfiguredTitle() {
		return TEXTS.get("Product");
	}
	public MainBox getMainBox() {
		return getFieldByClass(MainBox.class);
	}
	public GroupBox getGroupBox() {
		return getFieldByClass(GroupBox.class);
	}
	public TileField getTileField() {
		  return getFieldByClass(TileField.class);
	}	
	
	@Order(1000)
	public class MainBox extends AbstractGroupBox {
		@Order(1000)
		public class GroupBox extends AbstractGroupBox {
			@Order(200)
			public class TileField extends AbstractTileField<TileGrid> {
			    	@Override
			        protected boolean getConfiguredLabelVisible() {
					return false;
		        	}
			        @Override
			        protected int getConfiguredGridW() {
					return FULL_WIDTH;
		        	}

			       public class TileGrid extends AbstractTileGrid<ICustomTile>{
					@Override
					protected int getConfiguredGridColumnCount() {
						return 4;
					}
					
					  public class SimpleTile2 extends AbstractCustomTile {
					  @Override
					  protected String getConfiguredLabel() {
					    return "Tile 2";
					  }
				} // public class TileGrid
			}// public class TileField
		}// public class GroupBox 
	}// public class MainBox 

}//public class ExampleForm 

public interface ICustomTile extends ITile {

  String PROP_LABEL = "label";

  String getLabel();

  void setLabel(String label);

  String getGroup();

  void setGroup(String group);
}

public abstract class AbstractCustomTile extends AbstractTile implements ICustomTile {
  private String m_group;

  @Override
  protected void initConfig() {
    super.initConfig();

    setLabel(getConfiguredLabel());
  }

  @Override
  protected String getConfiguredDisplayStyle() {
    return DISPLAY_STYLE_DEFAULT;//DISPLAY_STYLE_PLAIN;
  }

  @ConfigProperty(ConfigProperty.TEXT)
  @Order(10)
  protected String getConfiguredLabel() {
    return null;
  }

  @Override
  public String getLabel() {
    return propertySupport.getPropertyString(PROP_LABEL);
  }

  @Override
  public void setLabel(String label) {
    propertySupport.setProperty(PROP_LABEL, label);
  }

  @Override
  public String getGroup() {
    return m_group;
  }

  @Override
  public void setGroup(String group) {
    m_group = group;
  }
}

public static class SimpleTile extends AbstractFormFieldTile<AbstractSlideMainBox>{
	// AbstractSlideMainBox is my GroupBox Class
	public void setSlideName(String slideName) {
		getTileWidget().setLabel(slideName);
	}
	public void SetImageFromURL(String slideURL) {
		getTileWidget().SetImageFromURL(slideURL);
	}

	// and here is the most interesting thing, what I would like to avoid 
	@Order(10)
	public class SlideField extends AbstractSlideMainBox { 
	}
}

getTileWidget().addField(new AbstractSlideMainBox());