A group of child-block pins selected by a marquee that enclosed only pins
(no whole object). Entered from MultiSelect’s marquee. The action-bar
overlay offers Copy, a tag-visibility toggle, and Delete; the group can’t be
moved. A plain click clears it; a drag starts a fresh marquee.
Frame the given pins with a single rectangle around the union of their stubs
Corner rounding of the frame drawn around a pin selection. Shared with the
drag preview in MoveMultiPin so the frame keeps
its shape when a drag starts.
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.