Users must be able to select a parent itself with no children

What it is

When a parent is its own object in the data — a folder, department, or category that can itself be granted, moved, or tagged — people must be able to tick that node while every child stays clear. That is an explicit exit from the default “parent tick writes children.” Parent without children is not an accidental empty set from turning coupling off; it is a legal target state: the parent is in the set, the children are not. Without that exit, a tree can say “the whole branch” or “some leaves,” but not “this container only.”

Why it happens

Check-down occupies the parent box as a handle on the whole branch, so the parent’s own boolean has no independent door. If the product actually has two propositions — is the container in the set, are the members in the set — one box cannot hold both. People expand and clear every child, hoping the parent remains; default bubble-up then clears the parent too when children are all empty, so “container only” can never be reached. The exit is usually a changed gesture or a changed widget: a modifier-click on the parent, a menu “this item only,” or splitting container ticks from member ticks into two columns. Either way the two propositions come apart.

Once apart, the display must also be able to say “parent selected, children empty.” That is not mixed (mixed is some children selected); it is parent-self true and child-set empty. Drawing it as an empty box makes people think nothing is selected.

Where it stops holding

When the parent is only a group label, not an object, do not offer this exit — it would write an id with no business meaning. If bulk operations can only target leaves (tags on files, never folders), parent-only should be forbidden and explained. After a check-down has taken the whole branch, “change to parent only” is a shrinking of the set and must be findable, not hidden on a modifier only experts know. Assistive tech needs to hear “folder selected, contents not included,” not merely checked.

Applying it

• Ask first whether the parent is its own object. If yes, offer “this item only”; if no, keep parent-tick-means-branch.
• Make “this item only” discoverable in a menu or secondary click, and distinguish its parent display from mixed and from whole-branch selected.
• After “this item only,” children must all be empty and must not be recoupled by accident; ticking a child then enters partial selection.
• How to check: “add only this folder to the set.” Exported ids should be the parent, no children. If children come along, or the parent draws empty, the exit was not built.

Related

• Within the group: E3.16.1 Checking a parent usually selects all of its children · E3.16.2 A parent must show mixed when only some children are selected · E3.16.3 Coupling must stay responsive in a deep tree
• Adjacent: E3.12 Tri-State and Indeterminate · E4.06 Tree Controls
• Search terms: select folder only · parent without children · decouple tree check