@Override
protected DefaultPaletteBehavior createPaletteBehaviour() {
  return new DefaultPaletteBehavior(this) {
    @Override
    protected PaletteRoot createPaletteRoot() {
      return new GFPaletteRoot(diagramBehavior.getDiagramTypeProvider()) {
        // Override updatePaletteEntries (including createTool) to return an
        // org.eclipse.gef.palette.ConnectionCreationToolEntry with
        // PROPERTY_UNLOAD_WHEN_FINISHED = true
      };
    }
  };
}