Cannot click the "Option" Rated 4 out of 5 stars

I'm using the Firefox 13.0.1,
Sometime I open a lot of webpages, so one row is not enough to me.
When I want to open "Option" and change the number of row,
the system shows some strange message
I capped those message as photo,below is the link

Expect that problem,
it is a great Add-on
I especally like it's group in colour function

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

Already fixed

Please download the latest version at
The Mozilla review is slow so people don't have the latest version yet