AH, You’re onto something. I’m in Place Hierarchy which you say needs to be squished. So, if I don’t stretch enough to restore, they don’t reappear. I noticed it this afternoon (not at home and on a laptop) and then too, was playing with PH.
Right now, I’ve got it in two ‘columns’ at less than my usual working size. I NEVER use full screen as I have two browser windows open at all times. kiwitrees on left (Safari), research sites on my right (Firefox).
So if using PH as you designed, then user needs to know to stretch the window back.