unity-control-center background : Could not find settings panel "background"

I am running Ubuntu 14.04 (LTS). I have issue/bug for command : `unity-control-center` as below:

1. From manpage of unity-control-center (command : `man unity-control-center` or link:http://manpages.ubuntu.com/manpages/trusty/man1/unity-control-center.1.html) there is options available for Panel Names as below:

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PANELS
       The following panel names can be specified:

       background
           The background panel lets you set your desktop background.

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2. But when I run command : `unity-control-center background` following error/bug is generated:

$ unity-control-center background

** (unity-control-center:2823): WARNING **: Could not find settings panel "background"

And Main window of System Setting is opened instead of "Background Panel"

3. The correct option may be executed by command is : `unity-control-center appearance`.