It would be very useful (to me) if the Kendo MultiSelect widget supported the notion of checkboxes on each item and also optionally on each tag with optional header checkboxes for both all items and all tags. Perhaps this can be done with templates already. But when I tried it a couple years ago, I couldn't get it to work.
The PrimeNG MultiSelect widget (http://www.primefaces.org/primeng/#/multiselect) has checkboxes on each item and a checkbox in the header to select or unselect all items. (Ideally the header checkbox should select only already-fetched records when server-side filtering is enabled.) But it doesn't also have checkboxes on the tags or a tag-header checkbox.
The Wijmo 5 MultiSelect widget (http://demos.wijmo.com/5/Angular2/Explorer/Explorer/#/input/multiselect) has checkboxes on the items but not in the item header or in the tags or tag header.
The advantage of checkboxes in the tags is that the previously selected item can remain visible even while it's not checked/selected/applied/enabled ... whatever the semantics. Because the tags remain visible, they're very easy to re-select. The header tags make it much easier to select all, all-but-one (or a few), or none (un-select all), invert selection, etc. when there are many items to select.