Following are the different code tried to set the background color, but of no use.:
Please helpCode:field.el.dom.style.color = "white";
field.el.set().dom.style.background = "#FF8080";
field.el.dom.style.backgroundColor = "#FF8080";
field.el.applyStyles({
'backgroundColor': 'red'
});
field.getEl().dom.bgColor = "red";
field.getEl().dom.style.backgroundColor = 'red';