Having trouble with UI - Bug or Feature?

Unity Engine
1

I don’t want to send a bug report because I might not hear back about a solution or if I’m doing something wrong.
But as I’ve been building with the UI, getting familiar with how layouts work and interact, I came across something that has me stumped and it might be a bug or ignorance

they say a picture is a thousand words, but it’s not enough imho.

800×600 117 KB

to explain what’s going on,
the buttons expand height and width of the group,
the group’s width in a layout element to be 100,
the red window next to it has flexible width and height to fill the remaining space.
but it’s not working as intended.

2

so, a follow-up. having gutted all the layout stuff, for some reason the group was expanding itself based on its children’s flexible width but wouldn’t expand the image in some instances, ie: it’s bounding box was resizing, etc.

the group had to have no layout presets, just the layout script and the children had to have their size defined via layout script to expand the parent - a bit backwards for modern day convenience and reasoning.

makes me miss classic html designs