[Pharo-project] Nested progress bars

Hi all. Given the next code, could you explain me why nested progress bars are not handled by my #on:do:? How can I achieve that? [ 'main task' displayProgressFrom: 0 to: 5 during: [ :bar | 0 to: 5 do: [:x | bar value: x. (Delay forMilliseconds: 200) wait. 'nested task ' , x printString displayProgressFrom: 5 to: 10 during: [ :bar2 | 5 to: 10 do: [:x2 | bar2 value: x2. (Delay forMilliseconds: 200) wait] ] ] ] ] on: ProgressInitiationException do: [ :ex | ex sendNotificationsTo: [ :min :max :curr | self traceCr: curr ] ]. Thanks in advance. Martín