Function band_select

fn band_select(
    ui: &Ui,
    state: &mut LibraryState,
    rows: &[(Pick, Rect)],
    palette: &Palette,
)

Rubber band over empty space: press, move, and every row the band touches is selected. Derived from the pointer each frame — no state to keep. A press that landed on a row is left alone: that gesture belongs to the drag-and-drop source.