and we have the same change in MixedSound>>#add: leading to the same 
error in AbstractSound>>+

may be this has something to do with the sounds problem what where 
discussed recently ?

anyway the fix is easy, just add a #yourself ...


AbstractSound
+ aSound
	"Return the mix of the receiver and the argument sound."

	^ MixedSound new
		add: self;
		add: aSound;
		yourself


AbstractSound
, aSound
	"Return the concatenation of the receiver and the argument sound."

	^ SequentialSound new
		add: self;
		add: aSound;
		yourself


Stef