When I downloaded your example, it works perfectly. When I place a flex grid on the page (using either the default configuration, choosing a template, or building from scratch) I get one of two things. Sometimes I get a page that only Picasso could understand, or I get absolutely nothing.
I posted one example a couple days ago. To refresh:
This is how it looked in WWB:
![Image](http://www.ahgweb.com/wwb_14/flexgrid_in_wwb.jpg)
And this is how it looked in browser:
![Image](http://www.ahgweb.com/wwb_14/flexgrid_in_browser.jpg)
Currently experimenting with this file: http://www.ahgweb.com/wwb_14/flexgrid_notworking.wbs
When previewed in Firefox and Edge nothing in the flex grid appears.
If I try it in Internet explorer, I at least get something ableit the page is not usable.
Been through the tutorial a couple of times, but must be missing a step somewhere.