'single' — Clicking or arrow-keying selects exactly one node.
'path' — Like single, but arrow-key navigation always
selects the deepest visible child under the
focused node, keeping an entire ancestor path
"active".
'multiple' — Checkbox-style multi-select (toggle on click/Space).
How the tree-view handles selection.
'none'— No selection.'single'— Clicking or arrow-keying selects exactly one node.'path'— Like single, but arrow-key navigation always selects the deepest visible child under the focused node, keeping an entire ancestor path "active".'multiple'— Checkbox-style multi-select (toggle on click/Space).