UX… we could probably discus pixels and icons all day and still not agree on it :-)
Since Mendix 9 (?) the Expand and Collapse All buttons have changed, it used to be a “+” and a “-” and now is a “˅” and “>”. Where the ˅ will expand and the > will collapse.
The “>” icon is shown in front of collapsed items in the App Explorer, clicking it will expand it. For me clicking on a “>” means expanding things, but to expand everything I need to click on the “˅” icon.
I suppose it seems logical if you see the icons as the result they will give, but each time I need to click them I have a small brain freeze.
I was totally ok with the + and – icons.