Dear Pharoers, thank you all for your time and great contributions! Here is a quick performance fix for Nautilus. In Pharo2.0a #20581 and previous versions, selecting the package menu with my right mouse button lasts too long; here is why: 95.4% {564ms} NautilusUI(AbstractNautilusUI)>>packageMenuBuilder 95.4% {564ms} PragmaMenuBuilder class>>withAllPragmaKeywords:model: 95.4% {564ms} PragmaMenuBuilder>>buildTree 95.4% {564ms} PragmaMenuBuilder>>collectRegistrations *90.3%* {534ms} CriticBrowser class>>packagesMenu: Solution, only call CriticsBrowser initialization when this exact menu item is selected. CriticsBrowser>>packagesMenu: aBuilder <nautilusGlobalPackageMenu> (aBuilder item: #'Critics Browser') action: [ | packages target env rules | target := aBuilder model. packages := OrderedCollection new. target selectedPackages do: [:p | MCWorkingCopy managersForCategory: p packageName do: [:package | packages add: package]]. rules := RBCompositeLintRule allGoodRules. env := (RBPackageEnvironment new packages: packages ). self openOnRule: rules onEnvironment: env]; help: 'Running critics rules on this package'. Maybe there are more