public SimpleItemListModel<T> setColumns(final int columnCount, final Function<T, Integer> columnSpanMapper) {
        this.columnCount = columnCount;
        this.columnSpanMapper = columnSpanMapper;
        triggerChange(ChangeType.COMPLETE);
        return this;
    }
The listener provided here will be fired for items where an action icon is set if user clicks this icon
main/src/main/java/cgeo/geocaching/ui/SimpleItemListModel.java