You could build a ListView with helper objects referring to the actual objects. The helper objects contain the information if it is selected or not.
Take a look at the Tag Selector widget which might be helpful for tagging
Hope it helps!!!
I would recommend using the popup-menu widget on a listview or datagrid 2 to get that fly out effect.
No sure if this is exactly what you want, but this might be helpfull: https://docs.mendix.com/appstore/widgets/label-selector/