Struct EditableDecl 

pub struct EditableDecl {
    pub value: String,
    pub rect: Rect,
    pub multiline: bool,
    pub obscure: bool,
    pub on_change: Arc<dyn Fn(String) + Send + Sync>,
    pub controller: Option<EditController>,
    pub layout: TextLayoutSnapshot,
    pub filters: Vec<InputFilter>,
}

What an editable widget declares onto its render-tree node each paint (D112) — cleared and re-declared every repaint, like hits/scrolls. The engine’s key/click dispatch finds this via the render tree, NOT a captured closure: computing a click->glyph position needs FontCache (!Sync, cannot cross into a Send + Sync closure), and mutating the caret needs Rc<RefCell<RenderTree>> (!Send, same problem) — both are reachable from engine.rs, neither is reachable from a plain Arc<dyn Fn + Send + Sync> hit callback.

Fields

value: String

rect: Rect

World-space rect this paint, for click-to-focus hit testing.

multiline: bool

obscure: bool

on_change: Arc<dyn Fn(String) + Send + Sync>

controller: Option<EditController>

Optional programmatic handle (D116) — None for the common case (an app that only uses .value()/.on_change()).

layout: TextLayoutSnapshot

Paint-time glyph geometry (D116 layer 3) — click-to-glyph, drag selection, and double/triple-click all query this with zero FontCache access.

filters: Vec<InputFilter>

Input filters (D116 Step 8) — see the module section above.