public class PreviewEditorPart  {
  @Inject
  private TestToBeInjected test;
....
}

public class TestToBeInjected extends Composite {

	@Inject
	public TestToBeInjected(MDirtyable dirtyable, final Composite parent) {
		super (null, 0);
	}

@Creatable
public class TestToBeInjected  {
	public TestToBeInjected(@Optional  @Named(IServiceConstants.ACTIVE_SHELL) Shell activeShell) {
		//super(activeShell, SWT.NONE);
	}
	
	@PostConstruct
	public void hello () {
		System.out.println ("");
	}
}

@Creatable
public class TestToBeInjected {
	public TestToBeInjected(@Active Shell activeShell) {
		//super(activeShell, SWT.NONE);
	}

@Inject @Named(IServiceConstants.ACTIVE_SHELL)
	private Shell activeShell;