Cannot validate macro

In WizardMacroBuild, modify #frontPage method:

fourthPage
| pane row titleLabel descriptionLabel tMorph descrMorph labelsWidth |
 pane := self emptyPane.
 row := LayoutMorph newRow separation: 4.
 titleLabel := LabelMorph contents: 'Title:' translated.
 descriptionLabel := LabelMorph contents: 'Description:' translated.
 labelsWidth := titleLabel morphWidth max: descriptionLabel morphWidth.
 row addMorph: titleLabel fixedWidth: labelsWidth.
 tMorph := TextModelMorph textProvider: model textGetter: #title textSetter: #title: ::
  hideScrollBarsIndefinitely;
  askBeforeDiscardingEdits: false.
 tMorph scroller
  setProperty: #keyStroke:
  toValue: [:event |
   tMorph scroller acceptContents.
   self changed: #isReadyToApply].
 row addMorphUseAll: tMorph.
 pane addMorph: row fixedHeight: titleLabel morphHeight.
 row := LayoutMorph newRow separation: 4.
 row addMorph: descriptionLabel fixedWidth: labelsWidth .
 descrMorph := TextModelMorph textProvider: model textGetter: #description textSetter: #description: ::
  askBeforeDiscardingEdits: false.
 descrMorph scroller
  setProperty: #keyStroke:
  toValue: [:event |
   descrMorph scroller acceptContents.
   self changed: #isReadyToApply].
 row addMorphUseAll: descrMorph.
 pane addMorphUseAll: row.
 ^(WizardPage applyPage: 'Give a name and a description' translated on: self)
  contents: pane;
  yourself