DateField loses readOnly property after page refresh

Hi,

I’ve created a Table that uses BeanItemContainer and custom TableFieldFactory.

TableFieldFactory has one main task - make dates in table read-only and set proper resolution:

public class CustomFieldFactory extends DefaultFieldFactory {
(...)
    @Override
    public Field<?> createField(Container container, Object itemId, Object propertyId, Component uiContext) {
       (...)
            result = super.createField(container, itemId, propertyId, uiContext);
            if (result instanceof DateField) {
                ((DateField) result).setResolution(Resolution.MINUTE);
                result.setReadOnly(true);
            }
       (...)
    }:

And it works as intended:
http://snag.gy/1JlYu.jpg

But when I refresh my page, instead of text representing my date, I see editable DateField, without any date set:
http://snag.gy/dHB9E.jpg

It seems quite strange for me and I don’t know why it happens.

Will be grateful for help!