public class DateFilterComposite extends Composite
{
    ...
    public DateFilterComposite(Composite parent, int style, boolean showSearchRun)
    {
        super(parent, style);
        ...
        Label test1 = new Label(this, SWT.NONE);
        ...
        Combo = new Combo(this, SWT.READ_ONLY);
        ...
    ...
}

DateFilterComposite {
    background-color: red;
}

.DateFilterComposite {   background-color: red; }