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FocusScope

FocusScope marks a subtree as its own focus region.

In practical terms, it tells the runtime that keyboard focus inside this part of the interface should be treated as one grouped area. When is_barrier is true, it also acts as a barrier that stops focus traversal from leaking through to surrounding content.

This is most useful for dialogs, popovers, menus, and embedded editing surfaces. It is not a general-purpose layout widget. If the only problem is spacing or stacking, use normal layout primitives instead.

Example​

use fission::core::ui::{FocusScope, TextInput};

let node = FocusScope {
    is_barrier: true,
    children: vec![
        TextInput {
            value: String::new(),
            placeholder: Some("To".into()),
            ..Default::default()
        }
        .into_node(),
    ],
    ..Default::default()
}
.into_node();

This is the kind of structure you want inside a modal, where keyboard users should stay inside the dialog while it is open.

Field table​

FieldTypeMeaningNotes / default behavior
idOption<NodeId>Stable node identity.Defaults to None.
childrenVec<Node>The subtree inside the focus scope.Defaults to an empty list.
is_barrierboolWhether focus traversal should be contained by this scope.Defaults to false. Set true for modal-style focus containment.

Focus and semantics behavior​

FocusScope lowers its children under a semantics node marked as a focus scope. It is primarily about focus behavior and accessibility structure, not about visuals. The children are wrapped together so the runtime can treat them as one focus region.

When is_barrier is true, this becomes the right tool for modal flows where tabbing or keyboard focus should not fall through to controls behind the overlay.

Specific advice​

Use FocusScope deliberately. Overusing focus barriers can make keyboard navigation feel trapped in the wrong places. The barrier mode is excellent for real dialogs and overlays, but it is usually wrong for ordinary in-page sections.

Pair FocusScope with clear visible structure, such as a titled modal or panel, so the accessibility structure matches what the user sees.

Overlay, Positioned, SafeArea, and TextInput.