The Hierarchy Field is used to select hierarchical data from a dialog containing a hierarchy control.
The input field's (readonly) "formatted" value is a collection of chips representing items chosen from a hierarchy, featuring:
a tooltip that shows the full set of selected item chips (enabled only when the field's edit dialog isn't open and there are more selected items than can be displayed given the width of the field)
an edit button (hidden if summaryView is enabled) that opens a dialog containing a HierarchyControl (operating in "select-single" or "select-multi" mode) via which the user may update the selection
The field, the dialog (and the Hierarchy control it contains) are all designed to react dynamically to changes in the screen real estate available to those components on window resize.