Why LayoutGroup and LayoutElement has a RectTransform width?

Hi everybody,

as in the title, why LayoutGroup and LayoutElement has a RectTransform width?

They are supposed to modify their size based on the children or on the min/preferred sizes, so why should I edit the RectTransform sizes? At least I expected it to be disabled.

This have really no sense to me, and driving me crazy.

Please help, thanks.

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