Is it possible to force child behaviour for slots?

Right now, I’m loving slots. They’re great and exactly what I’ve been missing, but there is one quark that is causing me extra time.

I’d love to be able to prescribe a child height/width behaviour for any elements that are added to the slot. I’d love to be able to say “I want any child added to this slot to have width property set to fill by default.”

An example where this is annoying. Right now, anytime I drop a container in a slot in my modal component, the I have to prescribe the height/width behaviour for the container instead of it snapping into place in the available space. In Menus, every time I add a new menu item or a divider or a heading, I need to select them all and say their width should be set to “Fill”. Its a small thing, but it adds up over time.