Rated 4 out of 5 stars

Sun's code is working but
there is a problem (minor)

Although the opened background windows is not in focus, it displays itself in focus in taskbar.

So to open the background windows u have to first click it to minimize then click again to open it in focus.

You can see it yourself

This review is for a previous version of the add-on (1.5). 

Fixed in version 1.5.1

Version 1.5.1 fixes the problem with opening background windows, and also fixes the taskbar button issue. All users of 1.5 are advised to upgrade to 1.5.1.