There is a bug in the ListField class for GXT 2.1.3 version.
Steps to reproduce:
Create an instance of ListField with multiple values in the store.
Call setSelection() selecting multiple values.
Add the field to a FormPanel and render.
Only one item will be selected.
This bug occurs because of a faulty implementation of the setSelection() method on the ListField class. During rendering the superclass' 'value' field is set to the first element of the selection:
Later the Field class' initValue() method calls the ListField class' setValue() method and this overwrites the multiple selection: