zhtml.Widget method "setDynamicProperty" has a bug. If you are trying to set disabled / readOnly property to null (remove state) after having the property set to true, it does not get updated.
I have fixed this issue in my project by overriding the method and changing

case 'disabled':
case 'readOnly':
	n[nm] = 'true' == val;
	break;

to:

case 'disabled':
case 'readOnly':
	if ('true' == val) {
		n.setAttribute(nm, val);
	} else {
		n.removeAttribute(nm);
	}
	break;

Bug is still present in 8.0.3.1 version.