Hi pavel to explain it to others was in 12023 UnhandledError>>defaultAction "The current computation is terminated. The cause of the error should be logged or reported to the user. If the program is operating in an interactive debugging environment the computation should be suspended and the debugger activated." ^ToolSet debugError: exception. and now in 12033 we got UnhandledError>>defaultAction UIManager default unhandledErrorDefaultAction: self DummyManager>>unhandledErrorDefaultAction: anException Transcript show: '*** EXCEPTION ***'; cr. Transcript show: anException; cr. Transcript show: (thisContext stack first: (20 min: thisContext stack size)); cr. anException isResumable ifTrue: [ anException resume ] MorphicUIManager>>unhandledErrorDefaultAction: anException "The current computation is terminated. The cause of the error should be logged or reported to the user. If the program is operating in an interactive debugging environment the computation should be suspended and the debugger activated." ^ToolSet debugError: anException. Now this raises an interesting question: we should start to think a bit more about the architecture of the system. For example: UIManager role vs ToolSet role for the UI do we want to have it based on globals or on exception. I discussed that often with lukas and we came to the conclusion that exceptions are better because we could trap differently per thread different aspects (If I recall correctly). Stef