Thanks for the replies. Dinjin, I'm aware that unexploded blocks won't stretch; it's just that when included in a stretch-invoked window, they will change appearance to denote that they have been covered, but remain in the same position on the drawing when the stretch operation is made. IFRs, I thought that, too, so I zoomed out to see if there were any "remote" signs of life when the block was clicked-on (a little indicator square way off somewhere) but this isn't the case. I'm very baffled.