I'm using Ubuntu 14.04 LTS and I'm using Compiz and its Wallpaper and Expo plugins.
Since yesterday, after every reboot my first wallpaper won't show anymore and the edge setting won't work, so every time I boot the pc I have to open compiz, removing and adding the setting in Expo and in Wallpaper.
I noticed similar questions up to older versions of Ubuntu but not for 14.04 and not affecting the Wallpaper plugin.