When a GroupBox is collapsible, you have to select if it should start expanded or collapsed. It would be awesome to make this selection based on a expression. When opening the page, the focus would already be on the correct (expanded) box.
I think groupboxes in general could use some love.
I'd also like the toggle button to sometimes be in a different location then the box.
Being able to toggle hide/show a container is just a super handy thing to be able to do.