Let's say you have 3 desktops, and you want them each to have a different background picture (because now you can do this). So you go to Desktop 1 and set the picture, then Desktop 2, set another picture, and so on. Then you remove some desktops because you no longer need 3 but lets say you now only have one desktop. Then, later, you create another one. However, the desktop pictures you previously set up are completely gone, you now have to set them up AGAIN, as every new desktop has the same picture as "Desktop 1". For this reason, there is no point to set up different desktop pictures for your different desktops, as with time it gets reset eventually. So the only logical solution is to have the same desktop picture on all your desktops. But to do that, you need to SEPARATELY specify the picture for each desktop. You can't just have one picture and set it to all your desktops with one click. If you have 5 desktops, each with the same picture, and you want to change their picture, you have to do it FIVE TIMES. What's the point???