Form.replace throws an exception

the code below:

Form form = new Form();
Submit submit = new Submit("ok", "ok"); // field of type button
Label label = new Label("lab", "lab"); // field of type other than button
form.add(submit);
form.replace(submit, label);

throws an exception: index out of bounds

the reason is that Form.replace assumes that control is always replaced by control, button by another button etc... which is not always the case
In the above example the function tries to replace submit by label in field list but submit is in button list