Can not add a CustomComponent( Composite ) to Layout

I have this code in the init:

final AbsoluteLayout al = new AbsoluteLayout();
setContent(al);
al.setSizeFull();
al.setVisible(true);
al.addComponent(new IngresarProducto());

“IngresarProducto” is a Composite (CustomComponent), the browser dont display the Composite BUT is there invisible (see the image). This same piece of code was working days ago in another project! What is happening? THANKS in advance!

P.D. Using vaadin 7, maven, vaadin plugin exp. in STS 4.2
12999.png

I find the answer in this post:

https://vaadin.com/forum#!/thread/284968