First off, your thread title is unacceptable. It gives us no idea of what your issue is. Something like "Simplicity wallpaper glitch" would be more acceptable.

The glitch you've described also occurs for myself. I don't know how to correct it but I believe it's because of the deskfolder.dll module. Since I don't find icons on my desktop useful I don't use it.

To find out how to add more icons to your workspace you should read the readme file that accompanies the Simplicity theme.