In short, because when you mark the top-most widget in the tree with a const keyword, all its inner widgets will also use a const constructor, so there is no need to add those extra const keywords. If a inner widget does not have a const constructor, then your code won't compile.
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In short, because when you mark the top-most widget in the tree with a
constkeyword, all its inner widgets will also use aconstconstructor, so there is no need to add those extraconstkeywords. If a inner widget does not have aconstconstructor, then your code won't compile.