Hello everyone - I am having problems withZope's Transaction manage which think it might be buggy. TM.py defines _registered as a class variable which seems to hold the state of an instance (whether it is registered with the transaction manager or not). method _register() registers the instance with the TM depending on the content of the _registered attribute. this however seems to have the additional effect to set the instance as changed and therefore and therefore a new version is stored in the ZODB. Additionally as _registered is defined as a class variable it is shared among threads and therefore one thread can interfere with the state of another. I have changed all references to _registered in TM.py to _v_registered and my problem (creating new versions for every call to FSSession) is solved, but I am not sure what other classes use TM.py. Also I am thinking of changing _v_registered to an instance attribute instead of a class attribute. Any thoughts?? Is it a bug of TM.py DC has promised many times to publish their model of the transaction manager and maybe a few usage comments ... which will save us *a lot* of time. TIA Pavlos