Isn’t this what you are looking for? https://appstore.home.mendix.com/link/app/292/
There is already a widget like this. See https://appstore.home.mendix.com/link/app/99/ and very similar – https://appstore.home.mendix.com/link/app/59/
The widget you provided is a AutoComplete. We am not looking for an autocomplete Rather a widget which will allow the user to select multiple Items into one single text box and also remove it.
In HTML CSS Design terms its call “MD - Chips”. Please Open the Below Link