Yes, it looks like that's the best way to do it. Also I note I that can get the background color to surround the check box by putting the whole thing inside a border box like this:
tb = textbox("Hi there! ", << font color("white"), << set font style("bold"));
bb = borderbox(hlistbox(checkbox("", beep()), tb), << background color("red"), << border(1));
nw = new window("My Window", bb);
Many thanks.