is there a class similar to a SelectWidget which allows to select multiple items from a list in the OOUI library? I want to use that in a MediaWiki VisualEditor instance I'm extending.
I guess I can also rewrite SelectWidget myself, but yeah maybe there's a solution already.
OOUI appears to have only CapsuleMultiselectWidget (tag list / capsule control).
Also, you should note this is a JS-only widget (no PHP implementation, or "PHP pendant" in OOUI-speak).
After quite an extensive search, it appears there's no simpler multi-select dropdown - there are a few open tasks to implement one: