Hi I wanted to fix https://pharo.fogbugz.com/default.asp?14845 Selecting a class and pressing command B+M raises an error so either we should check that the selected method is not nil (I do not like that much) or the key binding should not work on classes (preferred solution). buildBrowseShortcutsOn: aBuilder <keymap> (aBuilder shortcut: #browseSenders) category: #NautilusGlobalShortcuts default: $b command , $n command do: [:target | target browseSendersOfMessages ] description: 'Browse senders of the selected method'. (aBuilder shortcut: #browseClassRefs) category: #NautilusGlobalShortcuts default: $b command, $n command shift do: [ :target | target browseClassRefs ] description: 'Browse class references'. (aBuilder shortcut: #browseImplementors) category: #NautilusGlobalShortcuts default: $b command , $m command do: [:target | target browseMessages ] ^^^^^^^^^^^^^^^^^^^^^^^^^ description: 'Browse implementors of the selected method'. a "bad solution to my eye" is browseMessages self selectedMethod iifNil: [^ self]. <<<<< self browseMessagesFrom: self selectedMethod selector Now my question is then how can I find the different categories of bindings such as #NautilusGlobalShortCuts I tried to inspect a builder from the debugger but I got lost and should run to catch a train. Stef