This method removed a child box from the content children list of this box. This
method assumes that the child box passed in exists as a content child already. At
this point, the box that was removed has no parent. This does not destroy (delete)
the box.
var cont = scene.getBoxById("theTabs");
if (cont)
{
var bx = scene.getBoxById("talkTab");
if (bx)
cont.removeContentChild(bx);
}