Function agent_text_loci 

pub fn agent_text_loci(
    root: &dyn Widget,
    theme: &Theme,
    presence: &PresenceCtx,
    interactions: &[SemanticInteraction],
) -> Vec<(InvocationId, Rect)>

Where the frame with root draws each agent among interactions in its text, by invocation: the box its caret or selection is in rather than the control its action is bound to.