Propose column auto-completion for Design Sample choices

Hello,

Just as processors acting on columns propose auto-completion for choosing on which column to operate it would be cool to also propose this when using the following options in "Design Sample":

- Column values subset

- Stratified (nb and ratio)

- Class rebalance

> Example of a processor offering auto-completion

> While Design Sample does not offer

Finally, it seems that the Design Sample can't operate on newly created (in recipe) columns, which is a pain



Best regards