Function draw_pin_selection_frame 

pub(crate) fn draw_pin_selection_frame<C: Canvas>(
    data: &Drawing<'_>,
    pins: &[PinId],
    painter: &mut Style<'_, C>,
)

and labels, so the selection reads as one. Shared by the marquee pin group (MultiPinSelect) and the single-pin SelectPin tool so both render the same way.