Have you tried this widget? It seems to fit your case, and has platform support!
Regarding your error: I think you should select your ‘Data source’ entity over at least one association, starting from your context entity.
Try creating a many-many relationship and you will get to see the one level depth attribute while selecting the display attribute from Multi-select widget. Find the below images for your reference.
Hope it helps you.
So i wanted solution in 2 ways:
1. Existing thing should work as a Checkbox where i am able to select multiple answers but i was only able to single select.
2. or else I will use a ready made custom widget but i was getting error there.
My Solution :
Existing checkbox was allowing me to select only single answer So what i did was i enabled Editable on my list view and then i disabled Editable property on description and turn on Editable on checkbox and now i am able to multi select.