Function render_dragging 

fn render_dragging<C: Canvas>(
    data: &Drawing<'_>,
    painter: &mut Style<'_, C>,
    frame: DragFrame<'_>,
)

Draw a drag frame: the edited route in Editing mode (halo, no stored decorations — the document’s corner set is stale mid-drag), then the working state on top: the session’s hypothetical handles, the text anchors on the previewed geometry, each label pinned at its captured drag-start anchor, and the drag’s own emphasis (the projected segment for an edge drag, the grabbed-corner ring for a waypoint drag). Before the first Dragging frame there is no session and the stored set is still current, so the route draws as plain Selected instead.