It's time for our good deed of the day.
OptionGroup has a very simple method to turn on a multiple selection mode:
Take a look at the new interface:
As you can see, now the component is displayed as an assortment of checkboxes and the
getValue method (of both
Property) returns a Java
Collection (actually a
Set). This happens when we activate multiselect mode.
We are not talking about Java EE, but just in case, the correct ...