This is an issue that has recently started occurring on my computer. I haven't noticed it yet on my laptop (maybe because it hasn't updated yet), but every time I start a new session on the browser, the background wallpaper resets to the default. Unfortunately, I absolutely hate the default wallpaper filled with horrible swirls of color that comes with the browser (no offense to the devs, I just prefer minimalistic wallpapers). I'm not sure if its just me but I would love to be able to fix it so that I don't have to set the wallpaper every time I open the browser.