Look at the original archetype. It has a corpse link to BrokenWin. When you smash the window, it 'dies' and is replaced by the BrokenWin. That's why it appears to resize itself. Now look at the two child archetypes - BreakWinS and the other one. They each have corpse links to different archetypes.
Make a note of the scale property on your window, and go into the hierarchy and make a new one inheriting from BrokenWin. Add the scale property to the new archetype, and then give your resized window a corpse link to it. This requires a custom gamesys, see the new FAQ for details