Hello there!
Before I submit this as a bug as I couldn't find anything about it, I would like to ask if FF is saving the panels' resize presets.
When I expand the widget tree and pages horizontally, or vertically between the two, I can use those dimensions. But as soon as I open another section and back, say "Firestore", the panel sizes are reset. It's quite annoying as I have to resize them yet again... therefore, I just use FF default sizes..