qooxdoo : Image Button remove padding border? -

i have image button looks :

here code image button :

var button = new qx.ui.form.button(null, "myapp/test.png"); container.add(button, { left: 10, top: 10 }); 

how remove button border & padding ? want display image only.

note: container qx.ui.layout.canvas.

the border , padding defined button's decorator, nullable:

button.setdecorator(null);