Hi, I have a ZClass-based product ClassA. Then, I create a folder: $INATANCE_HOME/Products/ClassA And Then `touch refresh.txt` under that folder. And also create a __init__.py (for allowing PythonScripts to use more modules.) After all, I execute manage_refresh to fresh my ClassA(thought, the "Refresh" tab doesn't show up). Below is what I got: --------------------------------------------------------------- An exception occurred during the last refresh. Exception type: Duplicate Class Ids Exception value: None Traceback (innermost last): Module App.RefreshFuncs, line 182, in performSafeRefresh Module App.RefreshFuncs, line 171, in performRefresh Module OFS.Application, line 759, in reinstall_product Module OFS.Application, line 637, in install_product - __traceback_info__: eNotice Module App.Product, line 524, in initializeProduct Module OFS.ObjectManager, line 272, in _setObject Module OFS.ObjectManager, line 280, in manage_afterAdd Module ZClasses.ZClass, line 419, in manage_afterAdd Module ZClasses.ZClass, line 373, in _register Duplicate Class Ids -------------------------------------------------------------------Can I take this issue as a "bug" or I shouldn't abuse ZClass/Refresh like that.Thanks for your attention.Iap, Singuan