You can say `add:height:` in the layout.
You also have to add an empty row at the end that will take the remaining of the space, because otherwise the input fields will fill the window.
ui := DynamicComposableModel new.
ui instantiateModels: #(
gameName TextInputFieldModel
platform DropListModel
finished CheckBoxModel
description TextModel
).
layout := SpecColumnLayout composed
add: #gameName height: ComposableModel inputTextHeight;
add: #platform height: ComposableModel inputTextHeight;
add: #finished height: ComposableModel inputTextHeight;
add: #description height: ComposableModel inputTextHeight * 4;
newRow: [ :r | ];
yourself.
ui openWithSpecLayout: layout.