I've been running Mythbuntu 12.04 LTS for a long time and had a specific background image that was set. Yesterday I upgraded MythBuntu to 14.04 LTS. Today, I decided I wanted to switch my user interface to Ubuntu's default Unity desktop. After running into issues with lightdm not showing the proper unity-greeter (which is now fixed), I have the following issue once I'm logged in: I can't change the background image to anything. I either get a black background or it shows the previous MythBuntu background. But I'd like to switch the background image now and it doesn't do anything.
I have already tried deleting all hidden directories but to no avail. Anyone able to lend me a hand with this issue? Or is this maybe a bug?