Checkbox shows up as disabled

Question

I'm mistified why a checkbox would show up disabled.
What do I need to do to enable it? Already tried using String object for the requestInvoice property, does not help.

JSP:

    <fieldset class="aa-list-primary-indent">
            <label class="custombox-wrapper custombox"  data-behavior="custombox">
            <div class="control checkbox"></div>
                <html-el:checkbox  styleId="requestInvoiceCheckbox" property="form(creditCardForm).personalId.requestInvoice" />
                In need of an invoice (factura)
            </label>
    </fieldset>

Form:

    private boolean requestInvoice = false;

    public boolean isRequestInvoice() {
        return requestInvoice;
    }
    public void setRequestInvoice(boolean requestInvoice) {
        this.requestInvoice = requestInvoice;
    }

HTML generated by the browser (Chrome):

 <input type="checkbox" name="form(creditCardForm).personalId.requestInvoice" value="on" id="requestInvoiceCheckbox">

Answer 1

Sorry, it's a bad question. The CSS setup makes the checkbox look disabled, even though it is not. Bad CSS design. All the JSP/Java/HTML code above is fine.