I always have to put a rectangle of color in a group to defines its color, but the group itself is the right size. Why can't I just give it a color?

This is partially related to this idea:
https://adobexd.uservoice.com/forums/353007-adobe-xd-feature-requests/suggestions/15957478-relative-positioning-within-a-group

If I could give it a color and relative positioning, you would match the Figma constraints feature.