Comment #2 on issue 3472 by aplantec: Text selection problem in Pharo-dev 1.2 http://code.google.com/p/pharo/issues/detail?id=3472 It comes from SmalltalkEditor>>evaluateSelection .... rcvr class evaluatorClass new evaluate: self selectionForDoitAsStream in: ctxt to: rcvr notifying: editor ifFail: [FakeClassPool adopt: nil. ^ #failedDoit] logged: true. ... where the editor is passed as the requestor to Compiler>> evaluate:in:to:notifying:ifFail:logged:. It is bad because as a result of 'ProfStef next', the textMorph is set with a new text and as a board effect the morph paragraph/editor are released. So the editor morph should be passed instead of the editor itself. A fix is coming soon.