In the Designer there is a a Bug with the selection Box. I saw a forum entry from 2019 where it was fixed.
I am using 8.3.1.
It happens if:
- the root is a flex container
- in the flex contianer is a coordinate container
- the coordinate contianer is set to mode percent
- and the first element in the root is something like a button or a label
- no matter if row or column mode
Then the selection box is shifted. The shift seems to be the x or y distance, which the coordinate contaoner has from top or left.
Here some examples:
