This it's working.
I thought that this style could be inserted in a stylesheet, but it's not working, this was my mistake . However, in a widget html there are not problem.
But I have a new question, Is it possible to modify html code? For example: I would like to change <span>My task</span> or no show all instances, ...
I've trying to create a new web interface since header configuration in tab Implementation of Web Interface. But, when I save it always appear a message: "Error while saving",
I think that I'm doing something wrong. In this new interface I've put a report widget.
How I can to modify html code for to change basket popup?