Icons on Xfce Desktop come back

I am running Hiweed 2 RC3 (a Linux distribution based on Ubuntu), which uses Xfce as its desktop environment.

One month ago, for some unknown reason, all of the icons on my desktop disappeared after I restarted my computer. Today I was free to play with my computer and got the icons back as follows:

• Go to Menu>Settings>Xfce Setting Center>Desktop
• Click "Allow Xfce to manage the desktop".

Great! All icons came back, BUT, what on earth un-checked this?

Happy Birthday, Tianyi

Tianyi is the lovely girl of my friends, who are living in Paris.

This portrait was drawn from a photograph taken at her half year old. Her parents made a Christmas card using the photograph, so I drew this sketch.

Last time we met each other at Beijing, you just cried as long as you found I looked at you; next time I see you, I hope you could call me uncle in three languages

Happy Birthday, Tianyi!