[Pharo-users] my mistake on Spec?

Hi! I'm trying to write GUI element with Spec, Pharo6.1x64 on Linux. Do according to the SpecBooklet. Finished the fragment, and try do: ui := GUI_ListCourtCase new openWithSpec . -> #value was sent to nil. I look in a debugger and: *openWithSpecLayout: aSpec "Build the widget using the spec name provided as argument and display it into a window" (window value notNil and: [ self needRebuild not ]) ifTrue: [ "window != nil" window value rebuildWithSpecLayout: aSpec ] ifFalse: [ "If value = Nil --> send him a message ???" window value: (self defaultWindowModelClass new model: self). window value openWithSpecLayout: aSpec. self takeKeyboardFocus ]. ^ window value*