multi selection – A 2 step select

I would like to share with you my case study.

My user has to select one or more main categories for legal stuff. After this first choice, he has to select a subcategory of each main category and an amount.

I have imagined something like thaht, with the possibility to delete de selected category, whici will return in the main list.

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I will be happy to have some feedbacks.

Thanks and Enjoy.