Table edit date value with formatting

Hi,

I have table component with editable column "Date" . I used ColumnGenerator to change date editor format and resolution.
My Problem: Editor opens window with dates where I can choose date. After choose it puts the date to text field. The problem is that it doesn't save/commit/remember choosen value (for examlpe after filtering table).

Everything works fine with default editor. Do I have to add anything else to my code?

tabelaZadan.addGeneratedColumn("Date", new ColumnGenerator() {
            @Override
            public Object generateCell(Table source, final Object itemId, Object columnId) {
                Property prop = source.getItem(itemId).getItemProperty(columnId);
                if (prop.getType().equals(Date.class)) {
                    DateField df = new DateField();
                    df.setValue((Date) prop.getValue());
                    df.setResolution(DateField.RESOLUTION_MIN);                    
                    df.setDateFormat("dd-MM-yyyy HH:mm");  
                    return df;
                }                
                return null;
            }
        });

anyone?
I'm not sure if I'm doing something wrong or it is some kind of bug.