User Control does not work

I'm taking the first steps with regard to User Controls in Genexus and I started by creating this simple user control:

JScript Runtime Render:

function test1($)
{
    this.Width;
    this.Height;

    this.show = function()
    {
        ///UserCodeRegionStart:[show] (do not remove this comment.)
        var buffer = "<p> hello </p>";
        this.setHtml(buffer);

        ///UserCodeRegionEnd: (do not remove this comment.)
    }
    ///UserCodeRegionStart:[User Functions] (do not remove this comment.)

    ///UserCodeRegionEnd: (do not remove this comment.):
}

The only tab I edited was the one I just added the lines to:

        var buffer = "<p> hello </p>";
        this.setHtml(buffer);

When I add user control to a web panel, the result after running the application is an empty webpage, not even the page's footer and header appears.

I also followed the HelloWorld tutorial to make a User control, but the result of the page is also totally empty (blank). What's wrong here? Is there anything left to do?

I'm using version 3 trial.