Nicolas Cellier wrote:
> Yes exactly that's the problem and that's why I ask.
> I used it in a very controlled fashion over-protecting with a probably
> unecessary copy in the preamble.
> But you never know how the message will be used once you release it...
> Anyway, some benchmark would be necessary before touching these bits...

I'm actually in favor of making this the default behavior of #merge:. 
We'd need some operation (merged:?) that ensures a copy but I don't 
think that creating a copy on every merge: request is useful. 
Rectangle>>quickMerge: agrees.

Cheers,
   - Andreas