I get various error when doing pushdown. Pushing methods from MethodWidget to its subclass is a good test case. on ======================================================== showInstance ^ self model showInstance and methodsIconsCache ^ MethodsIconsCache okToChange ^ self model okToChange. I get parseTree = nil computePoolsToMove | poolVariables searcher | poolVariables := self poolVariableNamesFor: fromClass. pools := Set new. searcher := RBParseTreeSearcher new. searcher matches: '`var' do: [:aNode :answer | | varName pool | varName := aNode name. (aNode whoDefines: varName) isNil ifTrue: [(poolVariables includes: varName) ifTrue: [pool := self whichPoolDefines: varName. pool notNil ifTrue: [pools add: pool]]]]. searcher executeTree: parseTree ======================================================== I also got a problem that I cannot reproduce but having to do that may be the change was not recorded and the Undo was wrapping soemthing wrong. This would be great if one of you try to remove the AbstractMethodWidget using refactorings to spot the problem Stef