How does Edit Mode work on mobile version?

I turned it on so I can use minus and plus, I understand minus, thats perfect, I don't understand that after plus the text turns purple but why?

and my other more important question: After I logged off, and didn't play for 4 days, all my settings/presets disappeared. My idea was that I would play with Edit Mode on, for a week or so, and everytime I randomly see bones, eggs, chicken/rat meat etc meat, or anything that is common and cheap, I would turn these off. But now I open the app and I have to set everything manually off from the scratch, nothing kept "saved" ...is it normal, or is it a bug? how does it work?