public final <T> void selectMultiple(final ItemSelectModel<T> options, final Consumer<Set<T>> selectionListener) {
        options.setChoiceMode(SimpleItemListModel.ChoiceMode.MULTI_CHECKBOX);
        selectItems(options, selectionListener);
    }
Use this method to create and display a 'select multi' dialog using the model data provided
<p>
A 'select multi' dialog allows the user to select multiple (or no) value out of a given list of choices

@param options           the item select options
@param selectionListener convenient listener which is called when "positive" button is clicked
main/src/main/java/cgeo/geocaching/ui/dialog/SimpleDialog.java