Hi - I think I had this issue a long while back, but I just hit it again (desperately trying to get back into Pharo again)…
I was trying out Willow - and had a method like this: initializeContainerView | behaviorDetails scopeSelection | behaviorDetails := IdentifiedWebView forDivNamed: 'behavior-details' containing: WPPagerDutyUserDetailsView new applying: [ :div :constants | …. Where I had a class reference to: WPPagerDutyUserDetailsView, I deleted that class thinking I didn’t need it and then spotted the above method referenced it and so I brought it back via Epicea. However when I ran my Willow Application, my web page was showing an error message “Error, ObsoleteClassWPPagerDutyUserDetailsView does not implement….” - essentially it seemed like this method was referencing the class I had deleted and not the one I had restored. When I went back to this method and simply reserved it, everything worked properly. I recall Marcus (at the time) mentioning that the Opal compiler was supposed to detect these kinds of changes and rebind things properly - but it seems that this isn’t the case - or potentially restoring something from Epicea subverts this? I can raise a bug if its genuine - but I’m just musing on this at the moment? Tim